Professional license fees for retirees?

Yes, if you have the intent of making a profit. I'd say you must be trying to make a profit, advertising, etc, so if you just renew your license and do nothing with it, I don't think that would qualify, but as always need to see the specific facts.

Please ready business versus hobby first:

I read your reference. It has helped me sharpen what the problem is.

There is no point to having an engineering license except for earning income. To putter with electronics or computers as a hobby does not require a license except for a rare public safety issue. I keep the license current in case I can find engineering consultation. Such gigs have been very scarce over the last few years. If necessity drove me to seek engineering clients, getting a new license would be virtually impossible in my current situation. Fortunately, it is not a necessity.

My best analogy would be that of a retired physician. I suspect a physician would try to keep a license current just in case a good opportunity arises or it becomes necessary to practice again because of necessity. I presume that it would be difficult for a physician to get a new license if his original has expired.

The point was that you need to provide evidence that you intend to use the qualification to make money. So you have to show that you have advertised for business or applied for jobs requiring the license. Just the fact that it would be nice for you to keep the license in case some use for it suddently appears in the future without any input from you will be seen by the IRS as insufficient.

If one is still at risk (say one's work is warranteed, or still subject to inspection, or otherwise may require followup) I think it could be argued that one needs to keep the license even if there are no new revenue prospects.

An analogy might be a CPA keeping their license solely for the purpose of sustaining audits on past years' work. (Except CPA's may not do as much fixed-price work as engineers.)

Steve