It's your baby Rob, you can manage it however you want!

Even if your bin is full, it will shrink a whole lot. You might be shocked at how little material is actually left when it's finished composting. For this reason I add to it for a while, putting it through a hot cycle each time. Then, I'll allow that batch to sit and finish for a couple of months and work on a new batch. At some point, though, you do have to stop adding to the first batch or it will never quite finish.

For this reason it can be helpful to have several piles at a time. Everyone does their own thing, though. Over time, you'll find what works best for you.

Congratulations on taking the plunge into composting, and welcome to the forum.

Karen

Keep adding to it. I tend to chop up most of my compost material, turning often, and I add to one pile for about a month. By then, the first stuff is starting to get really done and the whole pile is much more heavy and dense. When I start to grunt too much trying to turn it, I start another one. The first one will cool down in a few days, and I turn it once more and let it sit about a week. It's pretty done by then, and I usually am just using it as a mulch anyway, so I start putting it out.

When full my compost pile will be 4 feet high and at some point I do stop adding to that pile and start another and in a while the height of that first compost pile will have decreased to 2 feet. So the bacteria will reduce the volume of material by 1/2. Just when you stop adding depends on you but keep in mind that that compost pile will never be "finished" if you keep adding to it.
Some people will say you can keep adding to that compost pile and just pull the finished material from the bottom, but I find that much easier said than done.

I build my pile and then just add grass clippings each time I turn it until it looks pretty well done. That way it will be sure and get hot each time I turn it.

The two-pile (or more) solution is really the only complete one to this. I keep adding until it's full or the middle of the season, then turn into the other bin and start fresh.

You'll find that if you fill up a bin the contents will shrink during decomposition, so you could keep filling it for quite some time. You have to say enough's enough eventually in order to use it without hitting undecomposed stuff.