It takes a lot, so only if I actually have free time but I will typically paint the minis for my party at minimum.
Spray primer first, depending on how you want it to look. Black makes shadows easier, overall darker. White makes colours brighter. A lot will use a grey because it’s a good in between.
I just pick a colour pallet I think will be nice for the mini and restrict myself to only a few colours then go for it.
If I was doing things like armies, then it’s a lot more:spray in base colour, then maybe paint in a secondary colour on details.