Side effects of Delaying Hajj, if one has the means

The Prophet (pbuh) has warned the following to those who do not fulfill this obligation despite it becoming obligatory upon them:

He who possesses enough provisions which will suffice for him to reach the House of Allah, and he does not perform hajj, then there is no care whether he dies as a Jew or a Christian. ~ Tirmidhī 812

In the above hadith, a Jew or a Christian is a metaphor which means it is as good as the believer in Allah dies as a non-Muslim.

Hajj is fard (mandatory) upon every sane, adult and healthy Muslim, when he has sufficient wealth to enable him to travel to and from the Ka‘bah. This will apply when the wealth required to take him is in excess of his needs (such as house, transport, clothing, etc.). He also needs to have sufficient wealth to leave behind for the needs of those who are dependent on him. Furthermore, the journey needs to be a safe one and a woman must travel with a mahram. As can be understood from the great virtues and stern warnings above, a person upon whom hajj is fard should endeavor to perform hajj at the earliest possible opportunity. In simple words - this year!

The Prophet (pbuh) has said: “The one who intends to go for hajj should hurry; for sometimes he can get ill, his conveyance can go missing or some other obstacle may arise (which will hinder him from travelling).” ~ Ahmad

The Prophet (pbuh) also said, “Hasten to do Hajj (meaning the obligatory Hajj) for none of you knows what will happen to him.” ~ Imam Ahmad, 1/314

Hajj has a Special Rank and Value

The Companions of The Prophet (pbuh) were keen to know the best deeds so that they can prioritize their good actions according to their value. In the following two hadiths, The Prophet (pbuh) highlights the special position of Hajj:

Abu Hurayrah (a.s.) narrated that the Prophet was asked, "Which deed is the best?" The Prophet said, "Belief in Allah and His Messenger." He was asked again, "What is next?" The Prophet (pbuh) said, "Jihad (striving) in the cause of Allah." He was further asked, "And what is next?" He (pbuh) said, "Hajj mabrur." ~ Bukhari 25/7 ... Hajj mabrur means hajj which is accepted by Almighty Allah.

In an authentic Hadith it is said that a man came to the Prophet (pbuh) and said, "O Allah's Apostle! I have enlisted in the army for such-and-such Ghazwa (holy fighting), and my wife is leaving for Hajj." Allah's Apostle (pbuh) said, "Go back and perform Hajj with your wife." ~ Bukhari 56/267

Ruling for the one who delays Hajj despite having the means

Whoever is able to do Hajj and does not do the obligatory Hajj, delaying it for no reason, has committed a great evil and a major sin. (Source) The only way to get out of this is to repent to Allah from that and hasten to do Hajj. That's because Allah says:

And Hajj to the House (Ka'bah) is a duty that mankind owes to Allah, those who can afford the expenses. And whoever disbelieves [i.e. denies Hajj, then he is a disbeliever of Allah], then Allah stands not in need of any of the 'Alamin (mankind and jinns). ~ Quran 3:97

Umar bin Al-Khattab (r.a), the 3rd Khalifah of Islam, once remarked: “I was about to send envoys to the towns (on the outskirts of the Muslim empire) to check on all those who have the means to make Hajj but do not perform it, in order to impose the Jizyah (tax) upon them." ~ Al-Bayhaqi. In another narration the words “they are not Muslims, they are not Muslims” are included.

Misconceptions and Lame Excuses

Many people delay the performance of hajj due to misconceptions which become lame excuses for not performing hajj. In sha Allah, the bullets below will clarify a few of these misunderstandings, so that those who find themselves in these situations can repent and make preparations immediately. (Source)

Many people have enough wealth for them to go for hajj, but they wait to accrue enough wealth so that their spouse can also accompany them. If the husband has enough wealth then he should go for hajj immediately. And if the wife has enough wealth, and she has other mahārim with whom she can go for hajj, then she should go immediately too. The Sharīah (Islamic law) does not give either permission to postpone the hajj and wait for the other.
Many people think that it is necessary that they make arrangements for their parents to perform hajj before they do. This too is incorrect in light of the Sharīah. Undoubtedly, to make one’s parents perform hajj is a great virtue and honour; however, if hajj is not fard on the parents, but it is fard upon the children, then they should not concern themselves with their parents' hajj at this moment and fulfill their own obligation. It is possible that in the children waiting for the parents – or in the case of the husband waiting for the wife or vice versa – the one upon whom hajj is fard passes away and is questioned by Allah for its non-fulfillment.
Others delay embarking on the journey until certain worldly tasks have been completed. Remember! The targets of the world will never end. If it is one worldly target that is the excuse this year, then it will be another next year. The Prophet (pbuh) said: “No servant leaves hajj for some worldly objective but that he will see the people returning from hajj before his worldly objective is fulfilled.” ~ At-Tabrānī
Some believe that if their children have reached a marriageable age and are not yet married, then the parents cannot perform hajj until the children are married. This too has no basis whatsoever in the Sharī‘ah.
Some delay in travelling as they have small children at home. Once hajj becomes fard, they should seek suitable relatives, friends, etc. who can look after their children whilst they go for hajj; and they need not travel for long due to their circumstance and situation.
Some delay their hajj as they think it is better to perform it in their old age closer to their death! This is a fallacy as they have no guarantee for how long they will live, and this idea is in complete contrast to the command of the Prophet (pbuh) to perform hajj at the earliest opportunity.
Some delay performing the hajj as they only obtain a set number of days off work, and they postpone their journey hoping that they may get more days off next year and can spend more time in the Grand Masjid of Makkah. This too is not a valid reason to postpone the hajj. They should go and spend whatever time they have available and absolve themselves of the obligation of hajj.
Some delay the hajj, as they cannot afford to buy gifts for people, thus deferring their obligation until they have enough money that they can buy gifts for their loved and dear ones. This again is not a valid excuse.
Some delay in going for hajj as they cannot afford the ‘five star’, ‘deluxe’ or ‘golden’ package. The Islamic ruling says, as soon as one can afford the cheapest most basic package, hajj becomes fard upon them.
Others can afford a package, but as the package includes a hotel which is far from the Al-Haram, they are not able to read all five Salah in Al-Haram. This does not justify delaying the hajj. Remember, as long as the five days of hajj are part of the package, hajj will be fard upon them.
Some do not go for hajj on the pretext that they are not yet ready to change their lives. Such a thought is from Shaytān. Do we think the same when it comes to reading Salah or paying zakāh? And if this is the case, then change your life, for it is obligatory anyway! Moreover, In sha Allah, through the barakah of hajj, the life will change for the better. Some go to the other extreme and have resolved to change their lives, but make comments such as, ‘My Īmān is not yet strong enough and I need to build on my Īmān.’ This thought too is from Shaytān.

Hajj is a very important fundamental which helps to make one’s Īmān stronger. It is the fifth pillar of Islam. Plus no one can guarantee if they are going to live next day. All the more reason for a Muslim to fulfill this obligation. The character of a good Muslim is that he submits his will to Allah.

To end, here's a noteworthy advise from The Prophet (pbuh):