I try and do a week long foreign trip every two years.
Sometimes a week just doesn't seem long enough.
I reckon I could do a month easy .
The last couple of years though I've been doing a lot more short sessions , 4-12 hours mostly instead of the the 48 hour sessions i used to do.
I think I up my game on shorter sessions and to be honest my catch rates compared to hours have probably improved because of it.