I’m quite confused with “How’s that for…”

In “How’s that for endurance?” are you asking if something will resist or remain undamaged? Or are you saying: “look, this is really resistant”?

In “How‘s that for size?” are you only asking if something is your size?

Thanks.

Question

I’m quite confused with “How’s that for…”

In “How’s that for endurance?” are you asking if something will resist or remain undamaged? Or are you saying: “look, this is really resistant”?

In “How‘s that for size?” are you only asking if something is your size?

Thanks.

Answer

“Hows’s that for endurance” means “hey, look at how much endurance this thing had/has”.
How’s that for “ is a construction akin to “voilà”. It’s used to highlight something after it is demonstrated

Answer

It’s a little old-fashioned, but ‘how’ can begin an exclamation.

Grandmother to her grandchild she hasn’t seen for a long time:

How much you’ve grown! 
Look at how much you’ve grown!
(=You’ve grown a lot!)

How’s that for endurance! (That’s a demonstration of exceptional endurance!)

Answer

There's more than one meaning. It depends on context. With an exclamation mark "how's that for delicious!" would mean "wow, that tastes good!". With a question mark, it merely asks for someone's opinion. If you are in a store trying on clothes and the sales person asks you "how's that for size?", he is simply asking you whether you think it fits well.