Yeah i do make it general. General means most of S40 phones are better in battery life. (except if the phone and/or it's battery is faulty itself)

S40 doesnt suck up a lot of power compared to S60 but if the phone itself have a low capacity battery then it comes down to that. Battery capacity.

You also need to keep in mind that S40 have different versions that isnt that much different from one another (visually) but has better/lower power consumption in later versions (only on newer s40 phones). If compared with S60v3 fp2, i would dare say that s40 has the upper hand in low battery consuption.

Nokia 5310 uses S40 5th Edition and 6288 is a much older phone laa (it uses a much older s40 version) plus a lot of 6288 has problems concerning battery life and stability. So if you want to compare batt life with 5310 is i suggest you do so with a much newer phone with newer S40 version.