I agree...sometimes I just need a plugin to "spank" the audio signal...not a sexual thing...just a bit of herding frequencies...I have a LOT of the Waves stuff, but like you seldom reach for it...but fast and dirty Waves gets used.But the thing is that Waves plugins at least in terms of Emulations of vintage gear are much inferior to UAD.
I have all the Waves plugins and the emulations are very weak.
Also the code is much simpler.
UAD is high quality, the way they do the emulations is very complex and the code is intricate, that's why they're so good sounding.
Too have good quality you need processing power
Honestly the stuff I use most frequently from Waves is the oldest code they have, the Renaissance stuff is still very good plugins in my opinion...
The UAD DSP stuff is still what I use the most, even when I do have Spark versions.
I've been mixing too long to let CPU hits be an issue...thats old school training and there are tons of work-arounds.