I have been at my company for nearly 25 years, moving up through the engineering ranks and "across" to being a manager. I am pretty sure I've been underpaid for

I have been at my company for nearly 25 years, moving up through the engineering ranks and "across" to being a manager. I am pretty sure I've been underpaid for years, and that it has been a mistake for me to stay for so long. This is one of the many reasons I am starting to interview elsewhere (the other reason is that I just survived a layoff so deep I think it irrevocably damaged our ability to deliver our service). I don't know what types of offers I will get, but I will soon find out if that feeling and regret is justified.