Boost burns happen significantly more frequently than every few years. At 400km and a drag profile as large as the ISS, decay would take around a year or less,

Boost burns happen significantly more frequently than every few years. At 400km and a drag profile as large as the ISS, decay would take around a year or less, depending on attitude. A little bit more reading: https://space.stackexchange.com/questions/9087/how-often-does-iss-require-re-boosting-to-higher-orbit https://space.stackexchange.com/questions/9087/how-often-doe...