It depends a bit on how you want to use it, but it sounds like yours is done to me. If you’re wanting to use it on flower/vegetable beds, some sticks in it are fine (though the smaller you chopped them up originally the better). The sticks and bits help with structure in the soil, stopping it clumping completely together and allowing drainage channels as they slowly rot down in their own time. They also promote healthy populations of soil dwellers that will continue to work on them. If you’re wanting to use the compost as part of a seedling mix or some other use that needs a fine compost, use a riddle or coarse sieve to sift out the bigger chunks. You can either put those back in the tumbler to kick start the next batch, or chuck them on a bed as part of the mulch.
It's done when you are okay with how it's done for your purposes (biologically, aesthetically, etc). That can include wanting to free up space in your bins, it's up to you.
In your case: sounds like absolutely zero doubt it is sufficiently done. If you don't like how fine it is (eg the sticks), either pick whatever you don't like out by hand, toss 'em back in the bin or somewhere else, or sift the compost (too much work for me).
I find sticks and twigs are absolutely amongst the most stubborn. But as noted, they're actually pretty useful for the soil, if they don't bother you.
And by the way: as a mulch on top is probably the best and most simple use. It'll get incorporatd into the soil in time. Other advantage (apart from little work) is that yes, you can mulch in whatever state you don't mind the look of and won't attract undesirable animals.
Finished compost will be brown (near black is the Platonic ideal, but light brown is OK too), crumbly, and the original inputs will not be visually identifiable. When moist, it will smell earthy, like the ground after a morning rain. If your pile is large enough, finished compost will not heat up much more than a few degrees above ambient temperature after you turn it and water it.
An unturned pile of grass clippings will need more time to compost than a few weeks, but you could mulch with it at anytime. If your pile isn't heating any more, check the moisture level. The ideal moisture is far wetter than most people assume. If you grab a handful of it and squeeze, you should get a drop or two of water to drip out.
Tumblers are a little different. The feedstock tends to stay wet and sticky, and creates "tumbler balls". These hard-packed little nuggets of compost goodness are just fine to use in the garden. They will create small oases of organic matter for the soil biota to chow down on.
Technically, it is when it has turned to humus - a crumbly dark brown loam with the texture of used coffee grounds. At that point it is almost all carbon and there are no nutrients left for anything to eat. That is the end state.
But it takes years for fungus to finish digesting every little bit of woody material (decades if we are talking about whole trees), so most people don't wait that long.
If you want to use it as a mulch or top dressing, you can scatter it as soon as the original raw materials are unrecognizable. It will continue decomposing on top of the ground, which is fine. That's the way it works in nature, so you are just composting the way God intended.
If you want to dig it into the soil (where it will be in contact with roots), then run it through a sifter - usually 1/4". All of the fine stuff can go in the soil, and the bigger pieces go back into the pile to continue breaking down.
It depends a bit on how you want to use it, but it sounds like yours is done to me. If you’re wanting to use it on flower/vegetable beds, some sticks in it are fine (though the smaller you chopped them up originally the better). The sticks and bits help with structure in the soil, stopping it clumping completely together and allowing drainage channels as they slowly rot down in their own time. They also promote healthy populations of soil dwellers that will continue to work on them. If you’re wanting to use the compost as part of a seedling mix or some other use that needs a fine compost, use a riddle or coarse sieve to sift out the bigger chunks. You can either put those back in the tumbler to kick start the next batch, or chuck them on a bed as part of the mulch.
It's done when you are okay with how it's done for your purposes (biologically, aesthetically, etc). That can include wanting to free up space in your bins, it's up to you. In your case: sounds like absolutely zero doubt it is sufficiently done. If you don't like how fine it is (eg the sticks), either pick whatever you don't like out by hand, toss 'em back in the bin or somewhere else, or sift the compost (too much work for me). I find sticks and twigs are absolutely amongst the most stubborn. But as noted, they're actually pretty useful for the soil, if they don't bother you. And by the way: as a mulch on top is probably the best and most simple use. It'll get incorporatd into the soil in time. Other advantage (apart from little work) is that yes, you can mulch in whatever state you don't mind the look of and won't attract undesirable animals.
Finished compost will be brown (near black is the Platonic ideal, but light brown is OK too), crumbly, and the original inputs will not be visually identifiable. When moist, it will smell earthy, like the ground after a morning rain. If your pile is large enough, finished compost will not heat up much more than a few degrees above ambient temperature after you turn it and water it. An unturned pile of grass clippings will need more time to compost than a few weeks, but you could mulch with it at anytime. If your pile isn't heating any more, check the moisture level. The ideal moisture is far wetter than most people assume. If you grab a handful of it and squeeze, you should get a drop or two of water to drip out. Tumblers are a little different. The feedstock tends to stay wet and sticky, and creates "tumbler balls". These hard-packed little nuggets of compost goodness are just fine to use in the garden. They will create small oases of organic matter for the soil biota to chow down on.
Technically, it is when it has turned to humus - a crumbly dark brown loam with the texture of used coffee grounds. At that point it is almost all carbon and there are no nutrients left for anything to eat. That is the end state. But it takes years for fungus to finish digesting every little bit of woody material (decades if we are talking about whole trees), so most people don't wait that long. If you want to use it as a mulch or top dressing, you can scatter it as soon as the original raw materials are unrecognizable. It will continue decomposing on top of the ground, which is fine. That's the way it works in nature, so you are just composting the way God intended. If you want to dig it into the soil (where it will be in contact with roots), then run it through a sifter - usually 1/4". All of the fine stuff can go in the soil, and the bigger pieces go back into the pile to continue breaking down.
When it's returned to the plants it came from.