Devinator
Sūpā Saiya-jin Fō
Put as much as you can stomach
Stated. You should be able to adjust it as well. Once you see it come out of your paycheck, you can decide, hey, that wasn't so bad, and, leave it be or up it some even. Or, woh, that was too much, and cut back.
I am at 10% with no match. Definitely hurts each month, but, I know I'll be glad I did it when the time comes.