That’s when it becomes an issue and it’s a major part of what drove me from my previous work.
They shifted the goal posts in terms of grading structures and accelerated my development so they could get more work out of me for less. In 2 years I’d gone from entry level to having the same responsibility (and with higher expectations) as people who’d been there 10 years. But I was being paid about 75% of what they were.
They did try and offer me a bit more and promised this and that but their original offer was derisory.
It taught me to never, ever trust an employer when it comes to them making promises about pay/role development.