Even if I don't dive regularly, I like to keep my membership active to support DAN and all of the great things that they do. If finances are a little tight, you could just be a member and forgo the insurance portion until you are ready to dive again. I believe that by just being a member, you will still get Alert Diver, but I'm not sure. I did that for my son since he hadn't gone diving in 2 years. DAN member services is very supportive and understanding. When I wanted to renew his insurance again for a trip we are taking in December, they pro-rated his insurance and a family membership until our regular renewal in January. As I said, DAN is very accommodating.
Ellen and Andy - Thanks for your comments about DAN insurance. I agree. Would never dive without it, and unfortunately have had multiple occassions to use it over the years. Actually, a lot of nondivers buy it just for the evacuation insurance. I have a buddy who got hurt in a 4-wheeler accident while on safari in Africa and the DAN insurance expedited and paid for his air evac.
However, to answer Ellen's comment above - no, you don't have to buy insurance to get Alert Diver. It is sent free to all DAN members (North America).