How Often Should I . . . -- Bathe your ferret no more than once a month. -- Ears should be cleaned every 2 weeks, or as needed. -- Nails trimmed every 2 weeks (both front and back nails). -- Teeth brushed at least once a week. Take time to look over your ferret for lumps, bumps and any hair loss when you have your grooming sessions. It never hurts to weigh your ferrets at this time and keep a record of it.