I just hung my plasma on the wall - nor problems. I have the bracket drilled into the studs.

Is it necessary, over time, to take down the plasma and retighten the bolts in the wall mount that have been drilled into the studs? Is it also necessary to retighten the screws that go into the back of the TV, holding the arms up?

One thing I noticed, when I hung up the TV, one of the corners on the wall mount moved a little. It was originally flush with the wall, and it moved outward some, due to all the weight. Should I be worried about that movement? Will the bolt find its way out of the wall over time, due to the weight pulling on it? No other corners on the mount moved.

Sounds paranoid, I know, but I have never done this before on my own.

Unless you live near a railroad or in a quake zone.....the bolts shouldn't need to be re-tightened. If it was done correctly then you shouldn't have to touch anything until you get ready to either move it or put up a new panel.

I don't think that corner should have moved unless you missed the stud...

Definitely didnt miss a stud. I used a stud finder. It was hard as hell drilling into it, and even harder screwing the bolt into it.

I just think I might have not tightened the bolt enough in that one area, therefore causing the corner to pull away from the wall a little bit when the plasma was hung.

All other 3 corners are fine.

A few months ago I mounted a 42" panny with a monoprice wall mount. I replaced the provided lags with some more appropriate for the task. Because of the mounting holes on the panny the brackets that would attach to the plasma and then hook to the wall plate ended up being outside the location of the bolts, causing a slight flex on the mounting plate. So the edges of the mounting plate have flexed an 1/8" away from the wall but it is tight to the wall at the bolt locations. On a side note three of the original lags provided twisted off when trying to tighten them.

I don't think you have much to worry about unless the distance from the corner to the mount is significant. You should not have to take down the panel and tighten the bolts. What would probably happen (eventually) is that they would get overtightend and the heads would shear off. As an aside, when driving lag bolts into studs, you can lube the threads with ordinary hand (bar style) soap.

Thanks everyone for the input. I feel more at ease now.