I have done many jobs with reliable 50+ feet range.

I had one RP1 work very well for a 7500 sq ft house once... wouldn't do it again that way but it still works great.

I have had my share of 20 ft ranges as well.

The point being... Run extra CAT5! If you can't then look for wire to utilize (I have taken advantage of unused keypad and speaker wires). Always prime the customer for the potential of needing extra RM433s before the project begins and show up to the job with extras in hand so when the reception fails you look like the number one problem solver and integration hero!