A small collection of SLA batteries that I have:

12v 1.3Ah - Small backup battery used for my cathode lights, amateur radio and messing around with 12v circuits. Slightly neglected. It was found flat at 0.2v, and I managed to revive it back to almost full power. Has been deep cycled many times. 6v 1.3Ah - Battery for my old digital camera whose battery cover snapped off. Almost new, never been discharged. 12v 7Ah - Backup battery for various things such as the starter box for my nitro cars and small inverter runs. Came from a remote controlled boat as it was unable to power it properly but there doesnt seem to be anything wrong with it capacity wise. 6v 1Ah - Usually used in series to power my old remote controlled boat. These have been a bit neglected and only hold about 0.4Ah worth of charge now. I have many more SLA batteries in other applications such as torches, and bike lights. They are 6v 4Ah.