I think it's dependable on the period and area. The Vikings (or more properly Scandinavians) were notorious for their good hygiene, which, kind of, put to shame the Anglo-Saxons who bathed much rarer. In the 11th century, an otherwise unknown Trotula of Salerno wrote "De ornatu mulierum" a detailed guidebook for proper hygiene of women. John, King of England was known to take a tub along with a "tub-ward" on his journeys. In Poland of High Middle Ages public baths were very common and cheap, and Polish King Władysław Jagiełło (r. 1386-1434) kept a very high hygiene - even receipts for repairs and extensions to the baths he used have survived. Finally, there survived several treatises detailing bathing techniques, such as "Magninius Mediolanesis" and "Regimen Sanitatis Salernitanum" - both from Apenine Penninsula from 13th and 14th century respectively.