How many lenses is too many?

I recently read about GAS Gear Acquisition Syndrome and thought this question would be fun.
Canon has made it possible to use all EF and EF-S lenses with all of Canon’s new mirrorless cameras with the use of an adapter.
I'm keeping my EF-S lenses. Someday I'll make the switch to mirrorless.

Its N+2 Where N is the number of lenses you currently own.

Untill

N+2 = D-1

Where D is the number of lenses that will lead to a divorce

Unless that is the required outcome

Then its N+2

Because the optimal amount of lenses to own is N+1

Offcource examples of N+2 = S/3 working out fine exists but they are rare

S/3 AKA the 3 pair of shoes rule

I would have thought N+2/DI x PU where DI is disposable income, and PU is potential uses.
Having lenses that don't fit your current camera line-up at all complicates things a little, so you'd need to factor in things like what bodies you "might" have in the future (RF??)
Subtract number of lenses you own, but haven't used in over a year (I'm looking at you, 50mm f/1.8...) but don't include lenses that are just used as dust caps (75-300mm II)
Last lens I sold (300mm f/1.2 IS) was purely to cover cost of upgrading to 1Dx, so really I think it's all either swings & roundabouts - or smoke & mirrors.

joeseph wrote in post #19147501
I would have thought N+2/DI x PU where DI is disposable income, and PU is potential uses.
Having lenses that don't fit your current camera line-up at all complicates things a little, so you'd need to factor in things like what bodies you "might" have in the future (RF??)
Subtract number of lenses you own, but haven't used in over a year (I'm looking at you, 50mm f/1.8...) but don't include lenses that are just used as dust caps (75-300mm II)
Last lens I sold (300mm f/1.2 IS) was purely to cover cost of upgrading to 1Dx, so really I think it's all either swings & roundabouts - or smoke & mirrors.

Erh no.
That is an estimate on time to get there
because
N+2/DI/month (or year)

And unfortunately PU Is not a calculateable parameter, youd end up with infinite as result

When you have lenses you don't use for 6 months+

Mmmmmmm...... is there such a thing as too many?

Q: "What's your favorite lens?" A: "The next one."

I'm reminded of the quote from the late Texas Senator Phil Graham. I think it can apply to glass ...
"I own more guns than I need, but not as many as I want."