I bought my lifetime membership when they were selling for $199. If they ever drop to that price again, I suggest you consider. I have 5 characters on the account and my daughter has 3. (She also has her own account, but likes mine because I have a lot of the special uniforms and ships.) If the game is somehow still running when I kick the bucket, she has the passwords so can keep going. :-)
Having a lifetime membership is actually less stress. You play as much or as less as you want. Your stipend builds up over time and you can buy things things without expending any real cash.