I've only been riding for about 3 years, but in that time I've had 2 road bikes, 1 CX bike, 1 mountain bike, and have a new mountain bike on the way. If money were no object I'd have a fat bike, too.

First road bike I sold to a friend after a year of riding it. Current mtn bike will go to my kid.

Speaking of the kid, in the past 2 years we purchased a tandem so that he could ride with us (behind his dad) and he also has a CX bike. DH has also purchased in recent years a fat bike and a new CX bike. So in 3 years time our household's bike collection has grown by almost 9 bikes and only 1 bike has left our stable.