For new gun - always field strip with cleaning and lubing of every part of slide and barrel before first shot. I also cycle a full mag of snap caps to make sure the trigger works, etc. and then break down again and clean again - again before first shooting session.
After that, I will remove slide, barrel, guiderods/springs and clean after every range trip or two. I do a cleaning if not shot for 90+ days too. I have yet to completely disassemble any of my guns and clean every part. If I ever experience any problems with it shooting, then I would investigate the inner workings a little more thoroughly. I am not as OCD on cleaning my guns as some on here are. I use Hoppes 9 as my cleaning agent/solvent and RemOil as my slide oil. Always wipe down with a silicone cloth after any handling.
I wouldn't wait too long, though. I cleaned my Ruger Mark II (which involves removal of mainspring housing, bolt, etc) - for the first time since my dad gave it to me about 25 years ago - about two years ago and it was a complete b!tch to get apart and just as difficult to reassemble. Part of the difficulties were the logistics of how that thing has to be taken apart but also included the 25 year buildup of carbon, dirt, etc.