It wasn't for me. I had the same dilemma and decided to keep compost and dirty un-paper towels separately under the sink. Thus, the bin hold only "dry" trash and recycling. I know people said they used such settings and didn't have issues with stink but I didn't want to take my chances.

Compost goes in a tightly closed metal can (the plastic lid on the picture does not seem tight enough to me). I take it out when cooking. To avoid smells, I wouldn't keep the dish towels in a covered container either.

Just my 2 cents...

I wouldn't devote more than 15" for a trash. You can still get trash and recycling in that. Compost doesn't belong anywhere near that as it will encourage fruit fly infestations. You want something with a very tight cover for the compost scraps, and just a plain bin for the dirty towels. Both of those can go under the sink. Use a pull out drawer on the bottom, and then do some custom created pieces to hold a cleaning caddy, the towel bin, and the compost bin.

Ours is 18 inches and that is because we needed an 18 inch cabinet - I would save the space for your baking area.
I toss my used towels into the laundry room - but it isn't too far away.
I store our compost in the freezer and then take out to the compost bin.

In my view, it depends on how your cabinets lay out. My KD felt strongly that we should do a 24" trash pullout because it would keep the lowers on that wall symmetrical (33-24-33-24-33). I kept complaining about the lost 6". But I went along with the KD and he was right. I looks much better and I ultimately found a way to use the space inside so as not to waste it.

How does the 18" or 24" relate to the rest of the space in that area?

Nope!

I installed a frame on my sink cab door to hold trash. It is sized to use grocery bags, and gets taken outside to our main garbage bin every few days as it fills. The compost is in a stainless steel pail on the counter, and it also gets taken outside when it is full. I consider my kitchen to be medium sized for my neighbourhood, although compared to many kitchens here on GW, it is small. I just couldn't justify the expense of new cabinets for the storage of waste.

Thanks, everyone - those are good points! I've never composted before, but our city is starting a pick-up program soon. So I don't know the ins and outs, but certainly don't want smells or fruit flies!

Nycbluedevil, the pullout will be in a 48x48 island, so two 24" drawers would be more symmetrical. But I'm willing to forego symmetry for more storage.

Hollysprings, good suggestion.on the under-sink storage. I'm definitely going to try to do drawers, I just hope mid continent or barker (my top two contenders) will work with me on that.

Typically trash can accessories are either 15, 18, or 21" W, but if feel the additional recycle space is worth it, go for it!

I haven't used that unit, but as someone who's devoted 33" of space for trash and recycling in our kitchen I say it's definitely worth it.

Given you mean composting as defined for city recycling pickup and not composting as defined by deliberately keeping the juiciest most nutritious food scraps for worms to feed on, it absolutely works in the kitchen as defined. I keep city compost in a large bin in my recycle center and it is great. We put fruit, veggie, meat and other food wastes down the disposal though, so the compost bin is only used for food packaging, paper towels and kleenex, banana peels and bones. I absolutely love the convenience of just opening the drawer same as for trash, and not dealing with a separate bin in a different location or tucked away in an undersink cabinet.

I think it also depends where you live. If you are in the north you can definitely do composting in a way you couldn't do in the deep south, re climate and bugs.

If you have a very small kitchen as you describe then the compost and dirty dish towels can live somewhere else.
I used to compost in one of those Lee Valley green compost containers. This worked well in the winter but we always got fruit flies in the summer. Fruit flies are a P.I.A. and hard to get rid of! Based on a recommendation I read her, we started keeping our compost in the freezer. I use those lined paper compost bags and it works great. Haven't had a fruit fly in 2 years and we will never go back to a compost container in a cabinet.

For garbage and recycle we have the rev-a-shelf two bin system in a pull out.

OK, sounds like we'll go the compost in the freezer route, and dishtowels can just get thrown in the laundry like I do now. Thanks everyone! One less decision to make later :)

I have a 24" one. It was designed for two cans, perpendicularly in the drawer. Skinny side to the back, if that helps.

I turned one sideways, so it's running side to side in the cabinet.

Behind that, I put my unused paper towel rolls, garbage bags, and plastic bag storage. It's worked out very well.

I put everything compostable into different areas in my gardens. In between layers of mulch, not in the ground. No need for instructions. The paper stuff I save for weed block in the spring, so that's in boxes in the garage.
Recycling goes out to the recycle trash guys 2ce a week, so I don't have to keep it.

I think now I wouldn't go with such a big drawer. However, this has been very handy. Astethically, it's good for my OCD eye.