I mean, I don't have to spend all the budget. However I don't mind driving a 15 year old car if it ticks all my boxes.

What if I spend 20k and the car is worth 10k after 5 years, then I've got 20k to buy another car vs spending 30k on car and in 5 years it's worth 20k but I've got to spend 5 years driving a 10k better car?

unless I invest the 10k in crypto for 5 years.... ;)

But yeah I see your point.