How long before it's reasonable to change a routine

How long should one do a particular routine (without results, of course) before considering a different one? Info appreciated. Cheers.

I change mine after two months of no gains.

Oden

Thanks for the advice. Appreciated.

Don’t change unless you go a while without gaining. If you change too much you will never find out what works for you and what doesn’t Patience is key in PE.