I found this very short talk (it's about four minutes so it really is short) from John Piper about aging and sanctification interesting and helpful.
At one point he explained that getting older doesn't equal sanctification. Certain desires - he listed lust and greed for money but you could add all sorts of other things like grabbing for power, covetousness and so on - will likely lessen as a result of aging, sometimes for physiological reasons and sometimes because these things simply become redundant after a certain point in your life. But just because these desires lessen or even disappear, that doesn't make you holier. It is a deep seated, growing relationship with Jesus that makes you holy. So it is important not to be fooled into thinking that you are growing in holiness if the aging process is bringing some of these urges under control. They would be the hallmarks of growing in holiness but they don't represent holiness in and of themselves. It seems so obvious as I write it down - but it's good to have teased out the distinction, none the less.
The benefit of aging, he said, is that "your resevoir of past grace is growing." Lovely. Your relationship with Jesus is all the more sure and strong because you can look back on an ever increasing collection of moments when you have seen God clearly at work in your life. That is very steadying.
The unexpected surprise, he said, was that at age 30 he thought that in thirty years time he would be thirty years more kind and thirty years more patient. But certain sins have remained and that this isn't necessarily the case. Good to be mindful of this.
May God himself, the God of peace, sanctify you through and through. May your whole spirit, soul and body be kept blameless at the coming of our Lord Jesus Christ. The one who calls you is faithful and he will do it.
1 Thessalonians 5:23,24