I haven't read all the comments, but one thing to keep in mind is that the pension rules can change. Dramatically. For example, the rules for my pension used to be that you need to be at least 65 with 5 years of experience OR you need 30 years of experience, OR you need age + experience to equal at least 80. Then you get 2.3% of the average of your top three annual salaries per year of service.
Now I think you need to have at least 10 years of service AND you need to be at least 62 AND you need your age + experience to equal at least 80. Then you get 2.3% of the average of your top five salaries per year of service. (Not totally sure about the current situation because I was grandfathered.)
The first change I saw grandfathered everyone within five years of retiring, the second change I saw grandfathered everyone within three years of retiring, and the third quite huge change grandfathered everyone with at least five years of experience. It sounds like DW is not likely to be within grandfathering range for quite some time.
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Another factor to take into consideration is diversification. Even if DW's pension invests the money in the same kinds of things you do, they have a pretty good guarantee which can be backed by current employees and maybe taxpayers.
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Assuming the benefit amount is based partly on DW's salary, that amount will lose value with inflation over the years in a way that your investments probably won't. However, your description makes it sound like they try to make up for that with a 3% index, in which case you can try to guess whether inflation will be above or below 3% over the next couple of decades. Or maybe that indexing only starts once she starts collecting; you might want to ask.
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So far as I understand it, most annuities suck. You'd think that because THEY can assume that you'll live to the average age that people live to, but YOU have to assume that you'll live to be quite old, that they can risk doling out a higher amount per month than you could. However, their fees are so gigantic that they actually do much worse than giving you 4%. Also, they can go out of business. I would much prefer to have a pension or to invest on my own than to deal with annuities the way they are today, and I'm extremely risk averse.