Repeating or clarifying proofs in cited papers Is it bad form to repeat proofs or arguments that exist already in cited papers (while making it clear this is not my own argument but from the cited paper)? Instead of just citing the argument... I find it more 'readable' if I rewrite the argument within my paper in my own words. Plus the original argument may be slightly unclear, and can be clarified.
Plus it makes the paper more self-contained.

It depends on how long the proof is (longer is worse, for your question) and how much of an improvement you are making (more is better). 
