Well to be honest I brought it for mainly testing Linux Distros and other OSes on bare metal, and as a second/spare computer. If actually need to use a notebook, I rather get something lighter and with a much longer battery life.4 hours is pretty good for a Thinkpad T430.
The T430s gets a bit less on an average life battery, generally.
You can always opt in for an ultrabay battery as well, giving it an extra two hours if you don't find much use for the optical drive or ultrabay expansion.
T450 can be had for less than $300 easily and is just as capable.
+$50 for a battery replace on a T430 seems overkill. I'd just get a used, 'healthy' bargain OEM battery and call it a day.