My club rule is that you have to fly with an instructor if you haven't flown a club plane in the last 3 months; and let's just say my club is fanatical about quality and safety. I think the 30 day rule that some clubs operate has more to do with their cash flow than your safety.
Having said that, I haven't flown for 2 months and my next session will definitely be back with my instructor - that's as a 65 hour ppl. Seems safest to check I'm up to scratch before flying myself or taking passengers again - if this damn weather ever clears up!
HH