League of Legends XXXVIII: Featuring Mumble, The Giant Halibut

[ex cathedra]

On the other hand, having to run back early or being caught with low life at the end of a clear could just as easily get you killed.

Exactly. I don't think people realize that is impossible to completely clear the jungle as skarner with boots+ 3 and stay at a health that enables ganking. You would either have to skip some jungle in order to gank (thus exchanging certain creep gold for uncertain kill gold) or start regen + 1 and take all the creep gold and have the possibility of perhaps getting a lucky gank before going base.

Does anyone remember Skarner's basic clear time off of the top of their heads?

Because it doesn't take much to realize that Regrowth+1 doesn't actually offer that much more HP than boots+3 immediately after your initial clear.

It's pretty simple. Regrowth pendant offers 3 HP/second. However, you have two health potions less than the boots start jungler. At 150 HP a pop, that's a 300 HP deficit that Regrowth has to make up. At 3 HP/second, it takes Regrowth Pendant 1 minute and 40 seconds to break even with the boots start in terms of HP and that's assuming that you're always at less than full HP and thus benefiting from the regen. Since Regrowth doesn't kick in until you start taking damage, and in a normal jungle scenario you'll never start taking damage until 1:40, you aren't actually any safer in terms of straight HP until 3 minutes and 20 seconds into the game. Even then, you aren't significantly ahead of the boots start until the 4 minute mark, and while you're marginally more capable of ganking with safe HP after your initial clear you're significantly less capable of ganking in the first place. Bootsless Skarner doesn't scare anyone.