Is one who spends money on luxuries instead of saving it for Hajj considered negligent, and does purchasing marital necessities take precedence over saving money for Hajj?

A Muslim must perform Hajj immediately if they find the financial ability, based on the Almighty's saying: "And [due] to Allah from the people is a pilgrimage to the House - for whoever is able to find thereto a way." As for someone who does not find sufficient money, they are not obliged to save it for Hajj or for Zakat (definition); because that by which an obligation is not fulfilled is not an obligation itself. Accordingly, there is no harm in buying essential and permissible necessities for yourself and your wife, and you are not required to limit yourself to only the bare necessities. However, when you accumulate the money and are able to perform Hajj when registration opens, then hasten to do so.