depends. with my ***** am, i ended up spending about 20k on it on top of the 6 i paid for it, because i did it a little at a time, changed my mind on some things, had to replace things i already had replaced to work with my new upgrades, when i probably could have gotten the same results for around 10k if i'd planned it out well and done it all at once.
if you're going to finish your truck no matter what, i'd say do it, if just saving up the money then spending it at once isnt a viable option. if you may change your mind, scrap the project, have other priorities come up in the next couple years, dont.