How long do you pump for at work?

how long would u pump for? Usually I️ pump for 15 min at home on low on my Medela pump in style but in the car I️ have to crank it up some since the power isn’t as strong and I’m noticing that even after 15 min I’m still getting some drops of milk, whereas at home usually by 15 min I️ don’t see drops anymore.

and I️ Remember reading pump til he last drop but don’t pump too long that it over stimulates you and I️ had a lot of issues with strong let down and it choking my baby so I️ don’t wanna over stimulate. So I’m just a little confused on how long to pump for 🙈 and on what strength