If you're in your twenties, 10% is enough for a normal retirement. If you're 30 I think it is more like 15-20%, which is still nowhere near maxing it for two people on $100k. You don't have to save that much because compound interest does the bulk of the work for you. Your friends probably are saving enough to retire on at age 65 or 70.

Personally I don't save anything outside tax advantaged accounts. I'm just barely able to max my tax advantaged accounts on $80k/year.

However my tax advantaged accounts total are ~$35k. $8k of that is an ESPP which I may cash out so I am not sure if it counts as "savings." But all told it's about 43% of my salary. Even if I do get a raise, I'll probably start contributing after tax to my 401k. That will give me an additional $31k of tax advantaged space per year before I have to look at a taxable brokerage account.