I run my tires at a pressure that is recommended by the tire chart, according to my axle weights. Once I determined that weight, I wrote it down on my compressor. I check my tire pressure twice a year, once during my yearly service and once in between servicing the coach. In 15 years of owning a DP, the tire pressure has only been off by 1-3 psi after six months and most of that may have just been a difference I outside temperature.
For the first 13 years, I didn't use a TPMS system. I now use one, but it's only to see if I had a tire lose pressure overnight.
I'm amazed at how many people SAY they check their pressure everyday. It's surprising they don't create more issues than they avoid.