Yeah, so the session extender is a requirement. The metal itself is too hot to touch your lips after a few higher level heatups.
I think you are good for about 6 hits on 5 before you'll want the extender, you can keep going without it but its hard to keep your lips pressed on bowl temp metal.
That's subjective, I ONLY use mine for bong rips. I've had at least 20 people (probably more, but 20 that spent a decent amount of time with the GH) in that sample set no one ever asked for the extender and heat would come up as a conversation topic everyonce in awhile.
I would also recommend the extendr since you can use it for bong rips, as for individual use, it will be up to you, everyone has different lip sensitivity but on balance I think more people don't need it for "ordinary usage" Definied as: Unit operating properly, using it by yourself (read you are just taking hits from it, other people if they are present either have their own device or use the GH at a different time) and just trying to get high.
The assumptions I make to arrive at MY definition of ordinary is my usage and experience were the consumers have in general been heavy consumers who both vape and smoke but in general smoke. (I in general vape and specifically with the GH but my friends for the most part still smoke.)
So you'll see for yourself but don't let speculation on heat which is up to the individual user prevent you from TREATIN YO SELF to the best vape available. My GH is my faily driver, I have it set to 3.6 (Tres Seis) and taking nice slow long rips (you can take ANY kind of draw you want, I'm not saying long and slow is "best" just that's where I gravitated too) without the extender now. When I'm home however I usually finish the bowl by cranking it up to 5 and using a bong, usually 2 great big rips left after 10 or so on 3.6.
That video was cool, I didn't know they had stickers now! Also using the tip to scoop bud up is clever! Nice tip! ... hehe see what I did there?