Frankly if you thought you could live on $1,000 a month, and you probably can. It would be best to have about 1,500 a month from interest. This way your principle grows faster than inflation, and you can keep ahead of the curve. Alternatively just a little bit coming in each year from paid work can really help add back to the principle.
Just 1,000 a year in paid work is the equivalent of having an additional 20,000 invested (at 5%) if you can pick up enough piece work to make even 5,000 a year, that's like having an additional 100,000 in the bank. Which would allow your principle to grow faster than inflation (this is the real key).