I'm a professional and owner of a small family-owned business. I live in beautiful (well, when it's not raining) Portland, Oregon, with my wife and our two teenagers.
For the last 7 years or so I've been collecting world-wide from 1840 (I actually don't have any stamps that old) to 1960 or so. Through
ebay, I bought several old Scott International albums which cover up to 1953 or so.
I'm mostly interested in politics and history as reflected on the stamps, so used is okay with me, especially if there's a readable postmark. I avoid MNH because I don't like to pay extra and they're harder to mount. (I bought some Vario pages for these).
I don't check for watermarks other than a visual inspection, and as the Internationals don't discriminate between watermarks, if I get into a country, such as India, where watermarks are important, I just save all the (apparent) duplicates on a separate page, maybe I'll check them someday.
I like preprinted envelope stamps, especially international, these used to be featured in international albums but a long time ago Scott made the editorial decision not to feature them except for the U.S.
I'm also interested in cinderellas, fantasy stamps, telegraph stamps, local stamps, etc.