The cross bike is used mostly in the fall, the road bike mostly in the nicer spring/summer days, the gravel bike sees more nasty weather and longer rides that aren't always meant for speed, just being out enjoying the ride. The MTB is for any time I feel like hitting the dirt and playing in the woods, while the track bike is just for the track. The single speed cross is half for cross season and half for trips into the city with the kids, no one is stealing my cheapie bikes-direct UNO even with the carbon rim upgrade but it lets me ride with the kids and get some effort in at the same time. It just means I have the bike for my intended purpose or mood, gets boring always doing the same type of ride every time.