1. Adjust brake and derailleur cables, maybe check bearing adjustments.
2. Some are shop people, some are home maintenance people. The "I'm leaving it in ... on Friday" part is one of the reasons for joining the latter group - you don't have to leave your bike anywhere, you do the maintenance when you want, and you don't lose the bike for days/weeks.
3. You'll find about 387239 threads on this topic in here, but answer is, it depends. If you're real anal retentive, you'll take the whole bike apart, clean every part and put it all back together after every ride. If on the other hand you have a life, a minor tuneup (clean chain/drivetrain, verify cables + bearings) evey 500-1000km and a major one (minor + bearings repack) every 2000-5000km should do it.