Re: OTJ and Testin
Maybe once a week to once a month.
You might also keep a daily log of the 5 Ps, so that if something changes, you notice it faster
Purring/contentment
Preening/grooming
Playing/normal activity levels
Peeing - half-cup blobs, not lakes, not deserts
Pooping - formed, neither too hard, nor too soft
Also
water consumption
food consumption
breath test - no smell of nail polish remover, nor a urinous smell (possible sign of renal disease), nor rank (possible infection; check teeth)
See my signature link Secondary Monitoring Tools for more.