Make sure there are no fees bundled in. My guess is you could get lower but with no fees they are giving you 4.875%. Make sure there are no doc stamps with your county or recording fees.
$40,000 at 5.1% is almost not worth it unless you can get maybe around 4.375% with no fees. Her advice to wait is probably good.
To the original poster - 4.875% in the current environment is not a great deal on a 30 year. I refied about $150,000 4 years ago or so at 4.75% on a 15 year.
Thanks for the info. That's basically what the banker said, she said to refinance for that small amount the rates would need to go down a good deal more in order to make it worthwhile..