Question about phone battery mark

My phone has a Li-Ion 1305 mAh battery and it last about 3-4 days with medium use. From ~85% to about 35-40%. I dont let it full charge or drink all the juice.
With super heavy use it lasts about two hours :P
Medium use: One or two phone calls per day (3Min Average per call) and messing around with apps, app store, checking email and surfing.
Super Heavy Use: Screen always open, messaging app running, 3G open. (If on WiFi it lasts 3-4 hours if i recall my calculations correctly)

it depends on the phone, but it's not a big battery, it should be fine as long as you don't have a lot of app running in the background :)

1800mAh won't last you long for gaming, calling, other heavy usage
Should be enough for medium usage especially if the screen size isn't too big.