Today something clicked as I was learning. Shifting and swinging your weight left and right helps me keep my balance and I can ride a whole street’s worth. But after 3 hours or so of riding I started to not go as far and started to fall. Is this because I’m practicing too much, or am I unlearning?
And also, does swinging left and right, as in weight shifting helps me, but is it correct technique?
Thanks in advance.
Whatever works for you is proper technique, When you start getting worse is when you should take a break.
Having just started unicycling at the beginning of Nov. I can say that you may find it useful to mix it up a little…that is, try different things like idling, riding forward and backward and also riding off curbs in addition to trying to go longer distances. I was just going to “mileage” when I started to regress…similar to what you are talking about. For the past few days, I have been focusing on hopping up curbs and riding off of them and I feel like me riding is becoming “deeper” and more solid… give it a try. 
Personally, I find that consciously twisting can be very helpful at times. I think it’s something the pro riders do without thinking, though probably not nearly as pronounced.
If you hold up a unicycle and spin the wheel, note the gyrating motion of the uni. It’s important to allow that natural gyration to occur while riding, and doing so requires (among other things of course) very loose hips. Not just hips that twist side to side, but 360 degrees of multi-plane motion. For example, hold up your hands right now and imagine each is holding a pedal, then turn the pedals around and around, like they’re on a real uni. Then, imagine you replace the pedals with the sides of your hips, and turn your hands again the same way as before. I think this roughly simulates how loose the hips need to be while riding. And swinging side to side can definitely help keep them loose.
But ----- keep in mind that I am not an expert. This is just what is currently working well for me.
Ditto on the consiously twisting, especially for us older stiff guys.
I have been working quite a bit with riding without my arms by holding on to the seat I can ride quite well with either right or left, but still working on both hands on the seat. I find that this is teaching me to ride with my hips controling the uni instead of relying on swinging my arms and torso around. I figure good control should make tricks easier.
I stop riding when I find myself falling off for no good reason. Typically as I get tired I ride over the front and the unicycle falls behind me.