Really depends.

My first one ,kudzu, took me over a year because i lacked the focus and did not want to grind mats. So i took it easy.

Astralaria was next and i found it so pretty i wanted to have it so grinded the achievements for it and it took maybe half a year.

Was lucky when i crafted aurora last year, since i did the druid backpack already when season 3 came out. Used the mats from the return to achievements so there was only achievement grind. Took me maybe 2 months. Vision aswell.

End of last year i made the first gen3 leggy with the staff of aurene and primordus variant. Maybe one month for that since you have all the mats from finishing EoD mostly.

Last month i made Exordium which i just bought most of the mats for which was a lot. But it was done in a few weeks because of that.