if one bearing needs replaced is it wise to do all?

What bearing? Generally if one is bad the engine needs a rebuild. You can band aid the engine with a new rod bearing but it probably won't last.

I believe you are asking about wheel bearings, While replacing both is a good idea, today's vehicles require you to purchase the whole wheel from the spindle out and are relatively expensive. So, if only one side is bad, I would just replace the one that is causing your problem and keep an eye on the other side for signs of wear and when it shows up, replace it.

Wheel bearing? Front of back? On a 2003 the fronts can be changed with hand tools. I believe the rear bearings have to be pressed out and back on. If the bad one is on the front, I'd change both sides, it's not hard.

Good to know that about an 03. I have an 06 and the whole assy is required.