Sorry but I check this board infrequently.
Normally we do a complete period probing every couple of years for most patients. For periodontal patients, we might do it every year. Between complete probings it is usual to spot probe areas with abnormal pocket depths. If one is really thorough, he will chart the number of bleeding points as well.
All dental management programs have a period chart module that lets you layer perio readings over time, so you can see progress or deterioration.