The length of time that you expect to keep the mortgage helps you determine whether it is worthwhile to pay points up front to reduce your interest rate. Unlike points paid on your original mortgage, points paid to refinance may not be fully deductible on your income taxes in the year they are paid.
There is a refinancing myth that says you should not refinance your mortgage unless your interest rate will be at least two points less. This myth is not necessarily true if there are other benefits to the refinance or other reasons behind it.
Many companies in this industry will do what ever they can to get away with charging you as much as they possibly can. Some of the ways they do this is not disclosing all the third party fees involved in a loan such as title insurance, appraisals, pre-paid tax and insurance escrows etc. It is important that you ask the loan officer you're speaking with about third party fees. If you don't they may not tell you and give you a good faith estimate that sounds fair, but at closing you'll find out that you have to pay a couple of thousand dollars more in fees you were unaware of. A good loan officer at a reputable company should have no problem disclosing all fees that pertain to your loan and should also make sure you understand what the fees are for.
Stick with a simple loan. It is easier to understand and less likely to get you into trouble. Adjustable-rate mortgages may seem like a way to get a bigger house now or to keep more money now, but when the rates adjust you can get into trouble. Avoid anything with a balloon payment. Just choose a simple 30-year mortgage you can easily afford.