Depends on what generation and if you have a precursor or not (or the money for one.)

Gen 1 is all about having the stuff. I already had done map completion in my main and had a gift of battle purchased ages ago for if I ever wanted a legendary. But I played engi so there was like zero reason to have one cuz they don’t show basically ever, and wasn’t a fan of any anyways. Eventually I got a precursor drop of the uh warhorn, so I made that and it basically took like… an hour… cuz I had everything and just bought some mats and etc.

Gen 3 Ive made a few: A few days of WvW for battle. Map completion of 4 maps (or lamp lighting of 4 maps) is a few days(maybe a day for each map). Getting imperial favours is maybe a day (maybe multiple if you’re doing a lot back to back and have nothing saved). Rest is mats. Plenty long term mats that can save you from directly purchasing by doing stuff daily/weekly: ASS weekly purchases and strike CMs, runestones daily across echovald. Fishing daily for ambergris. Laurels, extra provisioner tokens, etc. can help for mats for gifts. Overall, if I’m actually dedicated and have some good maybe 2 weeks. If not maybe 2-4 months to kinda passively get one.