Does a Mate of Tow Expire?

Does anyone know the recency for a Mate of Tow. The checklist just says “90 days of service in the last 3 years on any vessel.” Does that mean 90days service on any towing vessel or just any vessel in general? Aka if I don’t have 90 days on a towing vessel in the last 3 years will I lose it?

It’s the same for all officer endorsements, see 46 CFR 11.201( c)(1)(i).