Well, this is a bit difficult because I'm not sure whether or not you're talking about maintaining your current standard of living or not.
For example, I have enough in my savings account to maintain my current standard of living for 6 months. I have enough in an investment account to maintain another 6 months after that. So I answered 1 year.
However, I live in an apartment in Manhattan and pay $2400 a month in rent. If I were seriously hard up and didn't see any good prospects for finding employment in the future, I could move to Oklahoma or Nebraska or somewhere super cheap and find a place for less than $600 a month, which would extend my savings at least another 6 months (depending on when I decided to make the move).
I'm also 20 years younger than you and have only recently started investing (in the last 5 years).
Looking at my own retirement plans, it's estimated that I'll need about $1.8 million in savings to retire the way I want. For most people, the number seems to be between $1-2 million. So if you're wondering if you've saved enough for retirement, I'd judge it by those numbers.
Also, at your age, I'd suggest talking to an actual professional that can help you plan for retirement. Companies like Fidelity have people who can help you compare how much money you have to how much money you'll need, and also help you figure out how much money you'll need based on your expected lifestyle.