Not so much in the way of commitment, simply the right tools for various jobs.
I've a road bike, a hybrid and a rigid MTB. These all get used, although the hybrid gets used the most by quite some margin - shopping, away days, foraging in the hedgerows... That, and the fact it's the one parked nearest the door.
The ones I don't use are an older steel MTB and an even older rod-braked roadster.
This is what I built:
View attachment 647229
I couldn't find a junior MTB to suit (I'm 4ft 11) so I picked up an old Raleigh frame from the local tip and went from there. Got a LOT of help and encouragement from the guys on here during the build. It's great fun for riding gravel trails and farm tracks and also doubles up as my "mucky road" bike. We don't have much in the way of hills and gnarly stuff in the Fens, so it's got a touring-type drivetrain and commuter tyres.
Mmmm, Rolos are too sweet. I've currently got a box of hazelnut Lindor on the go.