Soon enough, you'll have enough fermenters (I just picked up two more) that fermenter capacity won't be your deciding factor as to whether to secondary or not. I have the following now:
5.5 gallon glass carboys - Quantity 4
7.5 gallon glass carboys - Quantity 4
8.5 gallon plastic bucket fermenters - Quantity 2
3 gallon better bottle carboys - Quantity 2
1 gallon glass carboy - Quantity 1
I'm now to the point that you can use a secondary or not use one, based on what I'm making. However, I'm getting into soured beers (Brett, Lacto and Pedio), so once I get enough of them going, I might be back where I was with my regular beers. I can see myself eventually having 6 soured beers aging, and be down to only 4 fermenters for regular brews. That wouldn't be too bad, but I usually do a couple of batches of wine each fall, and those tie up two fermenters for approximately 4-6 months. That would put me down to two 5 gallon or larger batch size fermenters. Have I mentioned that I'm planning on building a lagering chamber? Oh...........That will tie up a fermenter or two each time when I'm making lagers. Crap!
Maybe I should just go out and get about 10 more fermenters.
All joking aside, you can never have too many fermenters. It's better to have too many, so that you don't have to rack beer (exposing it to oxygen and contamination), when you don't want to. I only secondary when the beer calls for a secondary. If it's a straight ale, I have no problem leaving it in the primary for the 3 to 4 weeks it requires and then racking straight to a keg or bottles.
You can see though, that secondaries and the amount of fermenters isn't just tied to beer clarity. There is a lot more that goes into it.