OK, I've held my tongue regarding my claying opinion(s) for far too long, and I'm feeling chatty today, cause it's been a (insert Irish accent here) "GREAT day!" So for better or for worse, here's my take on claying.
It's a necessary evil. Sometimes, you get stuff stuck to your paint that just isn't gonna come off without either clay or an abrasive polish. Anyone that knows me around these parts knows that I like to remove stuff from paint using the very least amount of kinetic energy or friction possible. So I don't *like* to clay, but I do it cause occasionally it *must* be done. But my take is *only* do it when it *must* be done. If stuff is coming off your paint by using less kinetic energy, then use that instead of clay. No use in killing a fly with a sledgehammer, ya know?
OK, so there's that... clay only when needed. Then there's this (and I'm gonna get argued/flamed to no end for saying this, but that's 'aight): every time you use clay, you mar your paint. There, I said it. After holding my tongue forever to keep the argument and flames away, I finally said it. Every time you clay, you mar your paint. Wow, that's liberating to finally get off my chest!
You may not be able to see it, but the marring *is* there. Clay is an abrasive, and leaves abrasive scratches behind in your clear coat. And they build up, too. Just because you can't see them now, doesn't mean that you won't see them two clayings from now. I get so OCD about finding marring that it is really kinda stupid, but I can say with 100% confidence that if you are using clay hard enough to remove contaminants that won't come off with other means (and why else would you be using it???) that you are marring the paint. Yup, that abrasive clay is leaving abrasive scratch marks behind in your paint.
And to those that say (sorry, Accumulator, I think I might actually be disagreeing with you on this point!

) you can clay gently enough to leave your LSP intact, I say you aren't claying, then, because if you are using clay to remove contaminants you can't otherwise get off, you are rubbing more than hard enough to remove even the toughest LSP. Think about it.... you have stuff *so* stuck to your paint, you gotta rub it with clay. Do you think your LSP is bonded any harder to your paint than the stuff you're trying to get off by rubbing it with clay? IMO.... don't think so.
So what's a guy to do? You *gotta* use clay sometimes. It's a matter of damage mitigation; you're *going* to induce marring by claying, so do so in a manner that results in minimal marring for any given amount of contaminant removal.
This is where I stray yet again (and am gonna hear about it!

) from the "clay is clay" people. You don't use 150 grit sand paper to remove a scuff mark on a wood floor. So don't use harsh clay to remove bug gunk. IMO, using a good, quality clay pays off; for any given degree of contaminant removal, a good clay instills less marring. My all-time favorite clays, capable of really good removal for minimal marring are Sonus Green and Ricardo (you lucky Canadians). *Especially* the Ricardo. Today I had to *really* give my eyes a beating in the sun, trying to see the marring from claying with Ricardo. Yup, I found it, but it was the lightest marring I've seen, especially with how nasty the stuff was I was removing (very nasty hard water spots).
Wow, there's a lot of controversial stuff I said in this post... you guys take it easy on ole Supe in the responses, k? I'm in my heart attack years, remember.
I wonder how many posts it'll take before: 1. Someone *swears* they can clay without *any* marring, and 2. swears they have clayed two year old tar off their car without removing *any* LSP at all?

I'm gonna guess and say two...
Said in jest, honestly... you guys know I love it when you abuse me/refute/argue/flame. I live for it. It's like crack to me.:xyxthumbs