So far the only result of not doing a secondary is that my beers aren't as clear as I'm used to.
They aren't as clear a) when you bottle or b) when you pour the conditioned beer from the bottles into a glass?
a) Are you racking from the very bottom of the fermenter, sucking up trub perhaps? Many racking instructions I've seen stick the siphon or cane all the way on the bottom. It's much better to start siphoning from the middle of the beer, and lower the cane as the level drops. When you get close to the trub layer, and see trub being sucked up, stop the siphon!
b) All trub should settle on the bottom of the bottle. By pouring carefully and slowly and tipping the bottle back as soon as trub starts to appear in the bottle's neck, your beer should be clear. Longer conditioning and/or chilling time should clarify the beer.
Secondaries are generally not needed, or make your beer clearer. But they will increase the risk of infection and oxidation.
Racking/siphoning beer from one vessel into another, without introducing air (oxygen) is impossible, and it will harm the quality your beer. Unless one can perform closed transfers under CO2, exposure to air cannot be avoided. So those O2 (air) exposures should be limited (exposure is volume * time), and reserved for that short time when bottling.
IOW, especially for beginning brewers, for ordinary beers, secondaries should be avoided. There's nothing they (can) fix because there's nothing to fix.
If you're adding fruit (for a truly
secondary fermentation) a secondary could be used, yes. Take a look at pictures, most are filled up to the brim, 1-2" under the bung. Very little air in there!
If you're bulk aging, beyond 2-3 months, sure, get it off the yeast.
The one thing I've not seen much of is purging secondaries with fermentation gas (CO2). Then siphoning the beer into that, it remains under CO2. That would make a very good case for secondary some beers.