I've been bitten several times with skin punctures and had not one significant envenomation to date though one incident lead to a very hairy infection.
Most recently, my Daisy (who last appeared in a thread about shotguns where I touched on her almost (mere feet) getting taken down by Mexican Greys) was tagged 4+ times by a sidewinder that had let my two other dogs and my wife step right over it. We were stepping through a narrow wash on a single track and I had called Daisy to stop as I saw she was molesting some burrs up around her ears. As it happens, she stopped dead in the bottom of this very narrow and very shallow wash and directly on top of a partially buried sidewinder.
The buzz-worm started striking her just as I bent to her ears and she part leaped and part got tossed outa the wash but I wanted to kill the snake to take it to the vet in case I couldn't ID it - it hadn't moved in a sidewinder's very specific way yet - and also, I knew from experience that it is ironically very difficult to move successfully out of a rattlesnake's strike zone with out getting hit. They are remarkably forgiving if you don't get in that zone but once there, well, they hold a grudge.
So anyhow, I'm trying to get the stomp on this rascal while simultaneously not fall on the edges of the wash or have my luck run out in the envenomation department and watched this beast repeatedly hammer my Army desert boots with no (later determined) punctures and no apparent attempts to strike higher up my leg. The strike marks on the boot and the venom discoloration (will actually start to break down the leather) were an eye opener! When the snake finally sidled off at afterburner speed, identifying it by movement and an urgency to scoop Daisy off to the vet changed my priorities.
So, there's a quick run down on my having been bit from the Pacific coast to central Texas and having had lots of luck but seeing no particular need to over dress. Although, had I suffered Daisy's wounds and having seen the relative treatments of doctors, veterinarians and my own SF medics... Were I to get envenomated and don't have an SF medic around - I'd sure be wanting a vet.
Others have had very different and horrendous experiences on their one and only encounter but I just thought I'd throw this out there.
Now, Coral Snakes, Moccasins, Timber Rattlers... They're a whole other degree of squiggly Hell!