A large number of things can affect battery performance. As mentioned, the very first thing you should look into is the battery calibration. Drain the phone to the shut off point, and charge up ( best to do it while off. ) Since you are having issues, I would do it at least 1 more time. It's normally best to do 1 cycle every month to prevent the calibration from getting too far off.
Next, is that yes...bump charging almost surely harms the battery. Granted, it should be a fairly small amount, but it's not good to be charging, stop, charge, stop, charge. It's also likely that bump charging allows you to go beyond the intended 100%.
Another factor is/was the charge rate. With 2.1 our phones were charging significantly faster than they should have. ( Don't believe me? Grab your USB cable and read it. It clearly states 4-5 hours to charge. ) As you can imagine, charging the battery up 4 times faster than intended is not a good idea.
Charging habits. A lot of peoples charging habits are extremely detrimental to battery life. Leaving it on a charger all the time, using car chargers ( those car ports are for lighting cigarettes, they are not properly protected/filtered/etc. and can cause problems. Plus the connection is not very solid. Car chargers should be used as a last resort, not daily charge. ), letting the battery get and stay hot. Each of these things eats a tiny bit of life from your battery. Add them up, along with the previously mentioned and you can see battery longevity issues becoming a clear issue.
Also, Seidio 1750 mah batteries have been reported to be 1500 mah. That alone should bring their quality into question. I would not be too surprised to hear of them degrading faster than the stock batteries.
Oh, ( and heres one I'm very guilty of )...try not to use your phone while it's charging too much. If you get a call...unplug the phone before you answer. Battery about to die while you're on the phone? Consider hanging up or using another phone. Try not to run Pandora and/or tether while plugged in.( heres where I'm guilty...my phone has been my computers internet for several months. However, I do know how to extend my batteries life to help offset the harm I am doing here. )
All of these will generally only have a very tiny impact. Don't lose any sleep if you have some of these habits/issues. Consider if you can adjust things with minimal impact, but don't worry if you need to have your phone tethered to your computer for internet and streaming Pandora 16 hours a day.
The key is to not let these issues stack up. Some of them can even have a compounding effect ( IE: Battery getting hot, plus being tethered can be worse than the 2 separately. Keep it in a cool place, and check it now and then. If it's hot, take a quick break! )
Cheers!
