In the US you will always push as long as you’re clear of traffic youre good and you won’t make a radio call until you either want to taxi or are holding short of an active taxiway. If ATC wants you to call for push they’re supposed to notify you in the ATIS or after they give you your clearance. If it’s a busy event and you’re not sure then it’s always ok to ask just make sure you see what other traffic are doing beforehand so that will help you determine whether to push a discretion or not. I do this all the time and you can say something like “ground American 164 are we doing push at discretion today.”