I don't understand the question. One does not simply decide to stop falling down the rabbit hole, you keep going until it stops or you get taken down a different path. Never in my life have I made an active decision to stop learning about any one thing. You learn whatever skill is required to deal with the problem at hand and go on keep learning until you need a new skill or just get distracted.
But also you're making an extremely bad mistake in your thinking here. Being a generalist does not preclude being a master. In fact, I've found that in today's market you must have specializations. Right now I'm selling myself as an electronics engineer and embedded C programmer. But my deepest expertice is C#, where I consider myself to be a fairly high level expert. My current job is writing react native with some EE on the side.
You're trying to actively spread yourself even thinner which is a huge error. Knowing almost nothing about everything is not useful today, we just use AI for that. You need some real, solid skills to work from. You also need to be able to be a specialist and do specialist work because you are not likely to find a good generalist role. There aren't many such roles and they're getting harder to find.
But all in all my answer is no. There is no point where you should stop learning any one thing. Follow your passions and what's interesting. Finding a subject you're interested in and spending a ton of time learning about it isn't a bad thing. That's how you figure out what you like and how you build real skills. You should follow particular subjects into mastery because a generalist without any specialization is not actually very useful unless you're a world class engineer.
It's clichéd, but genuinely follow whatever subjects make you happy and find a way to make that work for you.
Grounding with a real scenario: You're doing your taxes. At what point do you hand off to a tax expert?
OP's asking a tough question.
At some point, it's impractical to try to be great at everything.
I never hand my taxes off to a tax expert.
If I run into a problem where I can't interpret the tax code myself, I'll schedule an hour appointment with a tax expert to get the answer to that specific question. If their answer sounds too good to be true, I'll schedule some appointments with other experts and take the most pessimistic answer. Ultimately, it's my responsibility that my taxes are correct, so I need to understand how they work.
I switched off of using tax software and do my taxes by hand, including rental income and stock sales. I'd estimate my tax return is 20-30 pages at this point.
If I ran my own company, I'd hand my taxes off to a tax expert at the point where filling out all of the forms represented such a significant investment in time that it detracted from my ability to run the company, but they would have to be significantly more complicated than anything the average person encounters. I would also hand them off to a separate firm if they reached the point where I needed credentials for the tax return to be valid - such as to assess the value of inventory.
It really doesn't take that much effort to learn how to do your own taxes, and the VITA program provides good free training in exchange for volunteering, which provides essential practice time anyway.
>where I can't interpret the tax code myself
That still leaves you making the crucial decision of when to roll in the expert with a layman's knowledge base & judgement.
Conceptually "I'll know when I don't know" is a very weak approach, especially on things like tax where the gotchas can be arbitrary & non-intuitive.
It's actually pretty simple. "Where I can't interpret the tax code myself" means "where my attempt to interpret the tax code leaves me with two or more possible interpretations."
The tax forms are very comprehensive. I go through each line of the 1040, following the instructions. Wherever the 1040 references some other form, I find that form, go through every line and follow the relevant instructions there. This approach has even gotten me through obscure edge cases like a company over-contributing to an HSA.
The tax code isn't magic and isn't full of gotchas. The rules may be arbitrary, but they're easy to follow and the IRS won't punish you as long as you're making a reasonable effort and report all of your income. There's an IRS help line you can call. People only really run into trouble when they try to take absurd deductions or claim that whatever tech investment strategy they've invested in doesn't count as income.
If you're scared of filing your own taxes, I really recommend volunteering for a local VITA program for a year.
As a generalist myself, I have decided not to require myself to become an expert in some tax issues, and so as a corollary decided not to complicate my finances with things that could invoke those issues.
I hand off to a tax expert when things are too complicated for a 1040EZ. Basically I hand off to an expert when the problem grows beyond my capabilities, same as any other kind of problem.
I'm not saying be great at everything, that's literally not possible. What I'm saying is that specialization is not antithetical to generalization. A good generalist should have areas of expertise because we can't cover everything. You don't need to be a world class expert, but you do need to find a niche for yourself and IMO the best way to do that is to simply follow what you find interesting.
> "too complicated...beyond my capabilities"
To OP's question, how did you decide that going further down the tax education wasn't for you? Was it really capabilities?
I propose that what you're really saying is that you're
a. not as intellectually curious about tax matters
b. or not concerned about the opportunity cost of your delegate being wrong
which makes it an easier choice to delegate.
When it is possible, when you can afford it and when such an expert existsand you know of them and can contact them.
Interesting factoid is that for many fields, such experts do not really exist. Unfortunately we do not get hired as researchers at this particular rabbit hole.
Tax and accounting is not one of those things.