I think Quora was the first to do this: https://dangelo.quora.com/10-Year-Exercise-Periods-Make-Sens...
And keeps an ongoing list of companies that offer extended exercise windows: https://github.com/holman/extended-exercise-windows
As somebody who has personally experienced every aspect of the stock option lifecycle (which fortunately worked out for me), I would never take a job at a company [1] if they didn't have an extended exercise window. The 90 day expiration period creates a massive gap between the risk/reward of equity for founders and the risk/reward of equity for employees, when the whole point of giving equity is to align those.
1: Assuming it was the type of company that compensated people with stock options
I personally think the status quo is insane, and I will never take another role with a options component of the package that does not have a policy like this.
A late edit: and you will get pushback for even asking. Apparently we're all supposed to pretend that we're never going to leave the company / we owe them our undying loyalty. I've previously taken the honest route when asked why I was leaving a job and said the ceo didn't deliver on her promises (growth, revenue), so why would I stay? That approach does not necessarily work well =P
I mean, part of getting promoted and learning how to rise politically in your career is learning how to lie.
Why did you expect honesty to work? You have to learn how to play the game, say the right things that people want to hear.
This requires converting all options to NSOs, and the tax implications of NSOs are not pretty. (From a tax perspective, ISOs aren't great[0], but they're much better for employees, by design).
[0] You have to pay AMT on the spread between the option price and current value at the time you exercise, whether or not the equity is liquid, so you could end up paying a large tax bill only to find that the company goes bankrupt before you have the opportunity to ever sell your equity.
Keep in mind for someone reading this comment, this is about private companies.
If you exercised, and another shareholder got unfair preferential treatment, you have reason to seek compensation or sue. If you haven't exercised yet, .... well ... not so much.
Also, many option contracts give you the right to buy X shares at price Y and do not make special consideration for stock splits - e.g. a 2:1 split would likely make your options worthless by halving the share price, and by halving the percentage of the company that X represents.
So, waiting to exercise until you sell is a very good strategy, except when it isn't - not very common, but you rarely get notified about these issues beforehand, especially if you are no longer involved with the company.