I can talk from my own experience. As I get older it's harder to get up the energy to practice, but sometimes there are special events coming up that make it easy. Right now, I'm practicing mandolin and singing every day, to get ready for a CD which Christopher and I plan to record in a couple of weeks. And you know what? Practice helps, even if you've been playing a long time. I'm playing and singing a whole lot better than I could a month ago. I was pretty rusty, but now I'm getting back into shape.
Is it hard for you to practice? Remember that it's a lot easier to start practicing and sound good after just a day or two off, than it is if you haven't played for a week. That by itself is a good reason to play a little every day-- you'll sound better when you play again. In fact, play every day if you can, even if it's just for 20 minutes. Or 15 minutes. Or 10 minutes. Then when you get a chance to practice for a longer time, it'll be easier to play and sound better!
As I've said before in these pages, 20 minutes a day is better than 2 hours on Saturday. If you go from one weekend to another without practicing in between, it can be hard to even pick up your instrument and play! So even if your schedule is rushed, when you have a few minutes in the morning or evening, play a tune or two. Your fingers will be glad you did.