From what I've read, disc access is the biggest battery killer. Ridge Racer wore down the battery in 3.5 hours (according to Gamesradar) but that has massive amounts of disc access.
They do state however, that the battery can be charged back to full within 2 hours.
If it means carrying more batteries then so be it - but owning a (currently gathering dust) 1st generation GBA which is unusable in anything other than perfect light, I'd happily sacrifice battery life for actually being able to see what I'm doing!
To be honest though, having been bitten a couple of times now - I'm gonna hold back on buying a PSP cos I just know in a year a better version will come out (yes GBA - I'm talking about you, you Judas!).
- S
__________________
|