The tuners also play a big role in this. I used to have the first year SE Paul Allender that kept being out of tune until I changed the tuners.
My Paul's Guitar and 408 also getting out of tune a bit after an hour of playing, but in Thailand it is quite humid so that may be the cause (not sure though).
The best "in tune" guitar that I have is Musicman JP6. I could play for hours with extensive trem and it only require slight adjustment (nothing is perfect for me).