My largest toy is the Super Big End which has a 7 1/2" circumference. I'm pretty happy with that, though I have thought about going slightly bigger.
I saw a plug once with a 10" circumference and momentarily considered it. I think it's quite unlikely that I'd ever buy something that large, but I've mentally set that as the point which I would never go beyond.
There are two kinds of limits, mental and physical. I don't mind going past my mental limits, but physical limits should be respected and gently enlarged if you want rather than racing past them in a display of sexual bravado.
So my size limit is 7 inches in circumference, and I don't think I will ever go past it except by MAYBE an extra 1/4 inch. Would you ever go past your limit? If so by how much?
I would and sometimes go past my comfortable limit. My comfortable limit is less than 2". Most of the larger toys are impossible and painful for me. I don't mind going a little bigger sometimes, but will not go to the limit of painful. Ever. If it doesn't go in with little discomfort, it doesn't go in. I won't force it.
Absolutely. I'm always pushing against my size limits, and finding new things to try. You've got to listen to your body and slow down when there's discomfort, though. There's no point in pushing your limits if it doesn't feel good or excite you.