Ask the lender or broker for a comparison of the up-front costs, principal, rate, and payments with and without this rate trade-off.
Lenders like pristine credit reports. If you have a bunch of open credit card accounts that you never use (and who doesn't?), consider closing them. It will boost your credit score and make you a much more attractive borrower to a lender. Then, a month after you've closed your accounts, go over your credit report with a fine-tooth comb. It should read that the accounts were closed at your request. (You don't want lenders to think someone cut you off and that you're a bad credit risk.)
If you have equity built up in your home, and you need cash, you have two choices: get a home equity loan or utilize cash-out refinancing. Each has its pros and cons, so be sure to evaluate your situation carefully prior to making a decision.
These days most people request a Good Faith Estimate (GFE), but have no clue what to look for on the GFE. Make sure you request a GFE that has ALL fees estimated and disclosed. This includes: origination points, processing, lender, appraisal, title, escrow... ALL FEES... especially the Yield Spread Premium or YSP.