If the doors are in good condition I'd suggest painting them over replacing them. It'd certainly be cheaper to paint them.
I agree with others here, just paint. Depending on the level of the you can probably get away with wiping them down with denatured alcohol, putting some cardboard down and doing a quick paint job. I recommend doing the same paint you have for the trim. I typically use semi gloss ultra white for all trim and doors. You shouldn't need but one coat because you are just freshening up the white, but again matching what on the trim is important. "White" next to "ultra white" will look a little gray. I take my door handles off for painting, but my big brother that's a professional leaves them on because he can cut around them faster than he can take them off/on.
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