[BleedinBlue]

For me it's a financial equation. I always have a number of projects going on at any one time but the time and money is usually focused on one set. For instance, I will always be collecting and upgrading my 1941 Goudey Master set. Whenever these cards come up I am in the market. A couple of years ago I started a T206 set and this was my primary focus but I was still looking for 1941 Goudey's. Because of the easy availability of the T206 cards and the significant size of the set I could not financially justify any other projects. Now that I have reached the 500 card number on the T206 set, finding new cards is more challenging. So, I continue to look for the 1941 Goudey's, I continue to look for the missing T206's but I have started picking up cards for my next project.

I think it depends on what you collect though. If you are working on a T206 set, there are so many cards that I needed to stay focused on small subsets in order to get some occasional gratification from completing a project. The problem was not availability of cards but funds. If I was collecting something scarce like T5's, I would make sure to go after each one because the next one may not come up again for quite a while.

Most of your sets are readily available. The issue isn't going to be finding the cards (generally) but rather finding the funds to pay for them. In this case I would prefer to go after the cards set by set until I neared completion on one. I would then start going after the next on the list until I was through with the project.