How many projects under way at one time?

Do you do one at a time, or have multiple going at once?

the most I had was 6
two in the spray booth getting sprayed.
one in the assembly bay (drive way) getting boxed up to send to the client
two in the manufacturing process. tenon, tongue & groove, mortising, etc.
one getting sanded for the spray painting.

One. And it sucks.

I'm sort of retired, but I suck at it because I work about 240 hrs a month. I sold my 7000 foot commercial building with all that glorious room and work in a three car garage at home now. I miss having a pet personal project or two tucked away for my own entertainment. Thought about buying a combination to save space but like my big separates so I put up with the lack of space.

Usually 5 to 10. Way to many that require me to keep a van full of tools & supplies and show up at job-sites. I am conflicted about what to aim for in the Shop. The big dream is to build one item at a time from start to finish with a price tag of $20,000. I have had some success having a small production line with several $1000.00 projects moving along together.

Four to six in various stages, with one or two in finishing. Always have at least as many in planning.
It helps me stay productive. If I hit a snag or loose interest, I move on to the next. I have one project that's been in the building stage for a couple years.
Space is not a problem I have about 5,000 for machining and assembly, with a dedicated finish room and another 3,000 for lumber storage.
Once being in the cabinet and millwork business is a big plus. Now retired.

Does in my head count? If it does, 100's. If it doesnt 1-3

3 is my magic number in the shop.

1-3 historically...

Usually no more then 3. No space for any more even small ones.
Good Luck

I do this for a hobby, so I try to stick to one at a time. I'm not interested in production so much as the process, so doing more than one can add stress, which runs counter to the reason why I do this in the first place. Though sometimes, like now, around Christmas, I have to bend the "rules".

The company I work for, which is a small production company, has the philosophy of never saying no to a job. So I constantly have to deal with and apologize to angry customers because we couldn't complete their work on time, because we always take on more than we can deliver. On the one hand, it's a total mess and I would never want to run a business that way. On the other hand, these customers keep coming back and the company itself is one of the most successful ones in this area. So it's clearly a valid business model, even if it seems like a terrible way to run a business. I don't understand it. And you think it would catch up to us one day. But 50 years in business, each year more profitable than the last, says otherwise.

Usually one, especially for a furniture build, if you don't count batch items. For example, a couple of weeks ago I banged out 3 custom charcuterie boards for gifts to dear friends.

How many projects under way at one time?

I would say, all of them!
No real number to give, as something always comes up and can easily push your primary focus to the back burner. I try to keep a few going in stages so that one is drying or has glue curing, while another is being actively worked on.
It can be difficult in a small space but you do what you have to.

2 to 4 but 3 is usually my magic number.

Full-time woodworker here and I've found it's not so much about number of projects but having them at different stages, so that there's always work to do and not everything is in the same area of the shop. Ideally:

1-3, depending on size, in the phase of design / consultation / procuring materials
1 large project ready to go, materials on hand
1 large project in the shop being made
3-4 smaller pieces, spec pieces, etc. that can fill in time

2 to 3 physical ones in the shop / installs is all I can take mentally and physically.

2 to 3 quotes seem to be due every week as well.

Whenever I'm on this site a lot, I'm trying to focus on quotes and not doing a very good job at staying focused. : )