You can stay up to three months and then technically have to leave for 30 days. If you don't have a stamp saying when you came in, you could go to a Swiss border and ask them for a stamp upon re-entry. Other countries won't give you one b/c of EU regs. (believe me, I have tried!) I initially thought that if I didn't have any stamps in my passport saying when I came and went then they couldn't kick me out. WRONG! Last year I had to leave (was given 5 days) and then come back after a month. The less you have to prove that you have been here legally, the more they will try to get you out. Bigger cities are harder to hide (believe it or not) but I have had great luck staying in a small village for as long as I want... shhhh don't tell!