I have 10, and they all see saddle time. 2 of them are currently not ridable (missing things like tires or cables etc) but they will be used once I finish them.
Some get used more than others. I typically only mountain bike in the late fall, winter and early spring while the trails are mostly quiet. My CX bike hasn't seen much riding yet, as I just got it/finished building it, but I am taking it with me this winter to see the inlaws and ride some of the gravel rails to trails.
Road bike 1: Cannondale Synapse - modern carbon fiber. Sees a lot of time during group rides
Road bike 2: 1979 Raleigh Competition GS- vintage. Sees a lot of usage on solo rides or rides with one or two friends. Recently used to complete a century
Commuter 1: 1987ish Peugeot tourer that has been modernized. Sees heavy use, 12 miles each way. 2-3 times a week
Commuter 2: Trek Soho Single Speed. Sees lighter use, usually 3-5 miles each way. Usually 2 times a week. It is lightweight and small enough to fit into my wife's car.
City Bike 1: 1991ish Peugeot ATB (Canadian made) Lives at work. Used for errands or to grab lunch. Will either be selling or giving to dad
City Bike 2: 1978 Raleigh Sports (English 3 Speed) Just got. Needs all new consumables (on order) and grease grease grease. Hopefully up and running by December.
Gravel/CX Bike: Converted single speed bike boom bike Royal Regina, made by Superia. Haven't seriously used it yet, but only because I just got it built up. Have some serious plans for it this winter.
Mountain Bike 1: Cannondale Trail 7 - Modern 29er hardtail. Bottom of the Cannondale line, but serviceable. I only tend to ride the trails when other people think it is too cold.
Mountain Bike 2: 1996 Proflex. Need to run cables still, and either track down special ferrules or get more cable housing.
Neighborhood Cruiser: 1972 Schwinn Suburban (Chicago made gaspipe). This one was a freebie. Somehow it is fully functional, minus the brakes, but needs a full tear down and rebuild, as well as new brake pads. Gets me around the neighborhood or to pick up Chinese takeout