This is personal, so might no work for you, but this is how I would go for a PB on my bench. I find it easy thinking about how to approach it as I always go in knowing what I'm currently sitting at and want to hit. If you have no idea then it's a little more difficult, tis a case of judging how each rep/set feels and increasing it accordingly.
All numbers are in kg, so this post might be ultra-useless.
175x1 - PB attempt
180x1 - second PB attempt
Might be too many reps for some people (and maybe for me??), but that kind of approach has worked thus far.