What asset allocation do you think you will want when you are retired? You need to work backward from that point to lay out a plan of what to do. And of course there are pitfalls along the way.
When you are five years from retirement, then...well, you will have just 5 years to go. If recessions make you nervous, then you are already in the red zone. So, you should have at least some of your non-equity assets by T-5.
You are investing in a taxable account, so changing assets by selling equity and buying new will trigger capital gains. You need to plan your tax strategy in those last year's to take that into account. If your timing is counting on a bunch of RSU's or some other large cash out at the end of your career, that would be an unfortunate time to add cap gains, too.
For those reasons, you may want to alter your asset allocation by altering your new contributions, and avoid the cap gains. Of course, this is limited by how much you contribute each year, vs. your portfolio growth. You may also be giving up some growth by buying more conservative assets. But you aren't making this move for growth, you are doing it to manage your landing in retirement. So, you may want to start this sooner rather than later.
The heavier your target portfolio is in non-equity investments, the sooner you need to get started. If you said you were 10 years out, and wanted to be at 90/10 by then, you could probably wait 5 years. If you want to be 60/40, you have a lot to do, and may want expert advice to help you navigate the best path.