I too have this problem. It is a re-occurring problem through my previous past hobbies.

I have not spent as much on my bikes as I have had on my wines, watches, cameras, and pens.

For biking though, I am now in an older, more responsible (yeah right!) mindset, and thus have set performance goals for myself before I would upgrade or buy another bike.

For example:

1) 300 then 400 then 500 mile per month riding average
2) regular weekly then twice a week 50 mile rides
3) completing metric and full centuries
4) 16 then 18 then 20 mph average over an hour
5) metric centuries in 3 hr 30 and full centuries in 5 hr 30
6) double metric century
7) 6000 miles per year
8) 20lbs weight loss
9) 10% power increase
etc., etc.

These can be simple performance goals but I find them as good motivational or self-deprivation tools so I do not just buy, buy, buy.

This should be similar to how we run our lives or businesses.

Graduate college or graduate school, first job, 401k, first car, marry, first house, first kid, 403b, second kid, 403b, second car, retirement plan savings, first company - minimal to no debt, then bikes!

First company hitting sales laddered targets and paying taxes, then investing in more people, equipment, and facility - sustainable growth and development without over-expansion and no debt.

Mark

PS. I wonder when I would allow myself that Parlee DI2 bike?