can you re-anno more than once?

If I've changed my mind, and want to re-anno, can you do it without losing metal and throwing off the tolerances?

No first-hand knowledge, but from what I've seen and read and partially guessing , it probably depends on what part it is. I recall seeing something along the lines of being able to re-anno twice. I would think your anodizer would be the best source for that info.

I really depends. Make sure you have someone who knows what they are doing working on it and explain the situation clearly to them.

I got the impression that its not necessarily the anodizing that causes issues as much as the stripping process. I had some lowers that were done and think the anodizer left them in the acid bath too long and some of the screw tolerances were a little wonky when they came back. I have also had someone say that a competent anodizer should be able to build material up somehow. I didn't quite get this part of it, but its how I understood it.

When you strip an annodized piece, you are removing the oxide layer off the surface. If that is all that is removed, it won't amount to any significant amount of real metal. When you perform the new annodize process, you will grow a new oxide layer on the surface of the aluminum similar to the thickness of the one you removed. This layer is essentially a matrix of hollow tubes, which is why they don't consume much of the surface metal. However, if you remove any of the underlying aluminum, then you change the tolerances of the part to a greater degree. A good annodizer can grow a thicker oxide layer to compensate for additional metal losses during the stripping process. The thicker the layer, the harder it is to consistently create. If the metal is lost unevenly across the part during the stripping process, then the surface will remain uneven after the annodize process.

you have about 3-4 chances for reanno, before things start to get dicey.

ive had an emag redone 3 times, it is loose but never a problem,
the anodizers I used were/are very good though.

The places you would need to be concerned with are places like internals, and anywhere something threads together. Those are the areas you will see the effect the most.

If you think you may want to redo the color over later once or even a few times I would recommend powder coating. I can essentially do that over and over hundreds of times, without any ill effects to the tolerances.

Really up to what you want, the look you are going for, and if you really think you are going to change your mind.