Company matches 4% for me. My first year I traveled a ton and had no real expenses, so I put 15% of my income in to my 401K to build it up. I’ve dialed it back to 10% now for the past couple of years and its amazing how fast it builds up. I actually hate receiving account statements because I’m like “Shit, I could buy an M3 in Cash!”
Since I have been doing it for so long I have adjusted my spending and don’t really notice the 10% less difference.
Oh, and you should be 100% in fairly high risk stocks while you are young. Better chance for bigger returns and you can recover if you take a hit. As you age, you should slowly move towards safer investments.