Should I leave myTouch Slide battery plug in all night? topic

I have had a secondhand myTouch 4G Slide for a week, came from an old nokia feature phone. The battery life was awesome and I noticed it was not using old stock battery but a new replacement battery written mpj on it. I usually plug it in and leave it plugged in overnight. Been read some posts about this, but opinions vary. Whether should I do that? Should I unplug once fully charged? Thanks in advance.