oric_dan(333):
OP, I hope you're not trying to power an Arduino using one of those measly little 9V batteries.
If I use these "measly little 9V batteries" with my arduino projects, which don't involve actuators but do have displays, I can have them run for a maximum of 2 days straight. If you just occasionally turn them on and look at them, they can last for quite some time. One of my projects from 2 years ago is still working with this battery since I turn it off after running it for a bit. These are two extremes but the OP really didn't say what amount of power is involved in the project so every 9V batteries are not totally unfit.