How much is too much to pay, for maintaining a Honda Civic 2000 per year, that is having 122000 miles on it?

Exclude insurance, gas, oil change… Just for mechanical maintenance.

Added (1). I live in NJ if that matters

My rule of thumb - In one year take the largest and smallest repairs you made and remove them from the list of repair bills - add the remainder of the repair bills and divide by 12 if the cost is over what you could afford for a new car monthly payment (including full collision insurance) it might be time to think about moving up.

Your car is older and it is at a time in its life where major parts start wearing out. You are looking at things like timing belts, shocks, plugs wires, maybe even ignition packs. These parts usually don't need replacing often but at or around 80-100K miles they have seen better days.