Most people (myself included) do note that there is a slight bump in score for being below 20% versus at 20% or more. And there is also a bump in score for being at 9% or below although you really have to play around to find the absolute sweet spot for your score.
The only reason to maintain credit monitoring is to ensure that no new negative information reports or to see that your creditors are reporting correctly. Just because you don't have any skeletons doesn't mean that erroneous information could not be added to your reports.
As far as point gains for Average Age of Accounts those occur on a much slower basis as it is such a small part of your overall credit score. I'm not really sure at what number of years the FICO algorithm rewards for AAoA. But your current score is great and should qualify you for anything you want that is within your DTI allowances. At some point all we are looking for is the nuts and cherries on top of the sundae.
Starting Score: 500's
You may or may not see an increase, personally I could see a few points being thrown your way. I've found the sweet spot to be around 9% or less. As far as the rest, how many open TLs do you have? As they age, you should see a few points here and there. Sounds to me like you're gardening a healthy report though. Good Luck!
July 2013 score: EQ FICO 819, TU08 778, EX "806 lender pull 07/26/2013
Goal Score: All Scores 760+, Newest goal 800+
Take the myFICO Fitness Challenge
Current scores after adding $81K in CLs and 2 new cars since July 2013
EQ:809 TU 777 EX 790 Now it's just garden time!
June 2017 update: All scores over 820, just pure gardening now.
One thing you could do to gain a few extra points is to pay a couple of accounts to a zero balance. FICO likes to see less than half of the accounts with a balance. You can utilize the credit all you wish, you just need to pay the account to zero a day or two before the statement date and then don't make any new charges until after the statement date. If you are trying to do this you just need to be aware of pending charges or recurring charges sneaking in between the time you pay the balance and the statement. But as I said above your credit score is really good and you are just going to be playing games to squeeze the last few possible points out.