Me 10 years.
Anyway, this qn is very wide...

First, you need to know what you are leaving for. Is it low pay? Lack of work life balance? Uninspiring job? Bad bosses or colleagues?

Once you identify the key pain point that drives you out from where you are, then that is exactly the area you should avoid when looking for job , and make a trade off via the remaining factors.
If your pain point is low pay, and yet you leave for a even lower pay job, then it defeats the purpose.

Note that there is no perfect job out there. Your dream job might not pay well. A high paying job may have bad bosses. A job with work life balance may not help in career progression.... Etc..

But I feel especially if you are moving within similar line and job level, you shouldn't upfront indicate a drastic paycut. Believe that your company now pays you for what you are worth. If you up front lower the pay expectation, is almost indicating to the potential employer that your actual worth is lower than your actual pay, which may cast an unfavorable impression on your confidence for your own capabilities.

But if you are moving say to your dream job in a completely different industry, and you know that industry doesn't pay as high as your current industry, then do be prepare for a paycut or even a drastic one.