Give instinctive training a go

One thing that seems to happen to a good majority of us in the course of our fitness journeys is the setting in of that dreaded boredom.
Boredom has probably killed more training routines than injuries, lack of time/money and laziness put together. You become stale and dread the mere thought of even working out.

That same routine that you loved so dearly and had been following for weeks or months suddenly becomes the antichrist. You wake up one day and all you can think is hell no, I'm not doing that again.
Sometimes it builds up over time, but a lot of the time it just hits you out of nowhere like a virus. Either way, it does you in and next thing you know a week has gone by with no workout. Then a month, then two, etc.

This is where instinctive training and a lack of structure can come in handy.

Instinctive training is pretty much what the name implies - Just do what your mind or body tell you to do that day. So what if you worked arms yesterday? Feel like doing them again today? Go for it.
 Been doing pushups for a week straight and kinda want to keep doing them? So what? Do it.

Everyone worries about "overtraining" the same bodypart(s) and such. But honestly, for the average guy? I don't think it makes a huge difference. When you were a kid did you worry about running around too much? Or think you'd get burned out from playing on the monkey bars two days in a row? I'd guess no.

If you're competing in some sport or something? Yeah, you're probably not going to get away with something like this too well. 

But if your most specific goal is just keeping a general level of fitness I think you can get away with being a bit more fast and loose with the rulebook. Not saying plans are bad at all, but I think for your average Joe, keeping it fun will go pretty far in keeping you active.

If you thrive better on structure and a firm plan, by all means do so. But if you're looking to break out of a rut, maybe just following your instincts will help a bit.

You can do this for as little or as long as you like. That's the beauty of rulebooks. Sometimes it feels good to just throw them away.