Honestly we lube up more than we clean. Cleaning only occurs after a training session during harmattan, or if we've been working outside for a long time and then we come into climate control, we will just lube off the condensation. The rifles are "older" so there are some areas prone to rust, like the FH, the outer barrel and areas where scratching normally occur.
If to give a number then about 500 rounds, but to contextualize that, it's unknown ammo, during harmattan season, and lots of dirt diving.
During monsoon season, then it's after every shoot and every shift will involve at least a win through of some sort of CLP.
If I was home bench resting or just shooting for shlts and giggles it's about every 1500 rounds I'll clean , but I lube up after every.