Just trimming should be fine. If it's important to you to do more than that, keep it to a minimum, unless you have a very responsible salon professional at hand. When I returned to the UK from a year in Germany, my mum's salonist was quite shocked at how my salonist in Germany had irresponsibly encouraged me to get more removed each time, the regrowth issues of which had caused quite a lot of scarring (from trapped hairs/blocked follicles). Digging hairs out of patches of inflamed skin and pus on your groin is not an enjoyable experience. Regular exfoliation is supposed to help prevent this but it doesn't really do much (at least, it didn't for me) and you can't exfoliate for a day or two after the waxing anyway, which is enough time for problems to start up.
Edit: The above is about waxing by the way. If I want to tidy things up beyond trimming I'll just shave a little off the top/sides, so it looks like a slightly smaller and neater version of its previous self. I still haven't worked out whether it's best to moisturise or not after - even perfume-free lotions seem to be unpleasant. But then damaged skin from shaving is also unpleasant.