moonlite
Kona Fan
This is it pretty much in a nutshell. Most of my rides are too short to require much in the way of fuelling apart from water. Getting that hydration in is essential. And then rest.Something that doesn't get talked about much is the need for rest days between exercise days as we get older. Once you get north of 50 it is important whether you are on the way to being fit, or are super fit already. Rest days can be doing absolutely nothing at all days and gives the body a chance to re-charge and repair.
I do 1 day on-1 day off with the odd 2 day rest, or maybe that with a block of 3 days on then 2 days off. Depends on the weather, mood, available time etc
It can get a bit random (tbh i think random is good and it does mimic what life would have been like as a hunter gatherer) at times, but i make sure i get the rest days in.
Another thing i have been allowing myself to do is to just back right out of planned hard efforts/long rides if my brain just isn't behind it. It could be signals that i have overdone it recently, or illness is afoot, or the mind just wants to look at stuff, notice things, and pleasantly pass the time. Life can be hard enough as it is without also stretching ourselves to meet self imposed goals.
I find my approach has evolved over the years to incorporate both 'science' and 'feel' -- heeding good nutrition, rest and stretching, but then also, per @Frankenorange above, taking it easy if things feel a bit lacklustre. The natural tendency is to push ever harder, so this is important.