5 days.
During my winter break in junior year, I was staying at a farmer’s house. It didn’t have heating, and the temperature outside stayed around -10°C the entire vacation — it was freezing! Taking a shower was extremely inconvenient. Since I wasn’t very active during the day and hardly sweated at all, I ended up going five whole days without a bath. As a southerner who’s used to showering regularly, I couldn’t stand the greasy, uncomfortable feeling anymore. So when I found out there was a public bathhouse not too far from where I was staying, I practically ran over there and treated myself to a long, hot, relaxing bath — even soaked in one! It felt absolutely amazing.
Better safe than sorry.