The 'old chestnut' again!
KN - the best bits of advice I can offer are:-
Refer to the Boeing 737-700 QRP where you will see an addition of up to 1100m in landing run required for 'no reversers' and 415m for one. Draw your own conclusions.
If the surface is very slippery, the wheel brakes can be virtually ineffective, so at ANY speed reversers will probably be better than brakes. Hence the Boeing recommendation to use up to max reverse if required down to 60kts
The best thing reversers normally do is put less energy (=heat) into the brakes which can help with quick t/rounds.