I've always pushed back against "all IP even on my own time with my own equipment." You're right that it's common in tech employment, but it's never been a deal-breaker for me.
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edited to elobrate You can almost always reach a compromise if you aren't a jerk about it and can show you understand the company's concerns. Typically I have it modified so that if I'm using their resources at all (office, computer, pen they bought me, etc.) it's theirs. Or if it's directly related to their core business it's theirs. Note that this is separate from a non-compete.
The key thing is to find some clear dividing criteria that is 1. generous to the company and 2. within my control (like choosing to use my own machine). Same idea behind the "one person cuts, the other chooses" method of dividing a cake.
I'm never going to give a company all of my output carte blanche. I want to contribute to open source. I want to make little (unrelated) fun things on my own and not worry about being sued if it ends up becoming popular. The company has a reasonable fear of people competing against them while on their payroll. Both sides can reasonably expect some protection.