It usually depends on the song length and difficulty, but in UTAU it takes me roughly a week, while in Vocaloid It can take me… nearly a month or longer. 
VocaVerse Network
Scarlet Illusion
vocaloidcreatornoob
What are other good parameters to use that you can recommend?
VyNancyV6
Usually one week
I'm a procrastinator
^<^
I'm a procrastinator
^<^
Scarlet Illusion
I recommend dynamics and brightness! Brightness is something I increase as the notes get higher, and decrease on lower notes!
As for dynamics, I’m still trying to find the way the works best for me, but what I like to do is increase for higher notes and decrease on the low notes. Still experimenting with that one, though!
As for dynamics, I’m still trying to find the way the works best for me, but what I like to do is increase for higher notes and decrease on the low notes. Still experimenting with that one, though!
cafenurse
when condensed down to just time on covers id say maybe 5 hours, 6/7 if you count time making videos. Im slow and work full time though so this usually happens over the course of a few months.
xuu
Depends how complex the song is, and how much I'm doing personally. Motivation plays a big part too. If it's a simple song I could probably finish the cover in half a day, but I've worked on covers for weeks before if it has multiple tracks/singers that need tuning individually. The best Vocaloid parameter by far is Brightness, it can do so much to a voice - I've seen people use a sudden cut in Brightness combined with a change in the Gender parameter to create a "falsetto" effect on high notes.
vocaloidcreatornoob
Do you make your own Vocaloid songs?
dreamsbrisk
Generally speaking, if it is the same theme, I will use the same cover, or the slightly modified version of the cover