I kind of have a mix, I try to get a form down, whilst being fast and precise before detailing.

Fast and loose is the only way to sketch if you ask me~
Don't wanna waste a bunch of time on a tightly constructed pose if you're just gonna redo half of it before you start inking.

When I did art things, I always started out fast and it looked pretty messy, but then I would carefully ink over the guide scratches.

I've long since stopped doing the art thing so maybe that invalidates my opinion, but that's how I did it.

Loose shapes so I can erase them easier when getting into details

It is better to take your time and do it right, after all when you have to work the image you will have to correct all errors of the sketch to leave it as detailed and clean as possible. A clean and well done sketch greatly facilitates future work imo :)

Maybe, but taking the time to do it right might be to start loose and tighten as you go! For me, it's about loose gestures first, and getting those tighter and more anatomically accurate later, because I value gesture and pose more than anatomy in my drawings. It always seems like trying to get clean sketches leaves poses stiff and less than interesting to me.

That's true, balance is the key! haha

I start fast and loose, and then come back to clean it up

Fast and loose helps with $/hour, since the sketch layer doesn't get seen in the final picture, but I find that for some reason having good details in part of the sketch helps me to make the rest of the sketch higher quality or something. So for now, nice and tight, though I'm focusing now primarily on simplifying sketches without a loss in ink quality.