I've consulted to many people on making the jump from self-employment to employee and the other way around - probably more of them making the opposite change.
As for the right time to change, that's a question with lots of factors and most of those are related to your situation. You say you've had steady work but that self employment is "more challenging". How is it more challenging, and which of those challenges will be solved by becoming an employee of someone else?
One consideration for the right time question is the value of your skills as a self-employed person vs the value of those skills on the open market.
15 years is a long time to be on your own (for the record, I've also been mostly self-employed for about 15 years), so I'm guessing you'll get at least a bit of resistance from employers thinking you may not be accustomed to playing the game of working with others in an office environment. If you have a highly marketable skill set and are in tech, and are talking to smaller companies that may not put much value on that ability, that may not be a non-issue for you.
I don't see the difficulty in establishing salary requirements, because the market dictates that more than anything else. You need to discover what your experience is worth on the market. Talk to an agency recruiter who places people like you in your area and they should be able to give you an idea better than the average websites. That value will have some fluctuation based on a number of factors, the value of benefits likely being one of them.
As for the right time to change, that's a question with lots of factors and most of those are related to your situation. You say you've had steady work but that self employment is "more challenging". How is it more challenging, and which of those challenges will be solved by becoming an employee of someone else?
One consideration for the right time question is the value of your skills as a self-employed person vs the value of those skills on the open market.
15 years is a long time to be on your own (for the record, I've also been mostly self-employed for about 15 years), so I'm guessing you'll get at least a bit of resistance from employers thinking you may not be accustomed to playing the game of working with others in an office environment. If you have a highly marketable skill set and are in tech, and are talking to smaller companies that may not put much value on that ability, that may not be a non-issue for you.
I don't see the difficulty in establishing salary requirements, because the market dictates that more than anything else. You need to discover what your experience is worth on the market. Talk to an agency recruiter who places people like you in your area and they should be able to give you an idea better than the average websites. That value will have some fluctuation based on a number of factors, the value of benefits likely being one of them.