Steeping and Boil times

I've been creating my own recipes and have always just defaulted to 1 hr steeping and 1 hour boil. I've seen others recipes which have shorter or longer times. What effects on the outcome of the beer does changing either or both times? If it makes any difference I steep @160f in 3gals, rinse with a gallon of cold water to boil 4 gallons for a 5 gallon batch.

Depends on your equipment. sounds like extract brewing? One hour is (usually) not needed, as todays malts convert in as little as 20 minutes, and can be verified by tincture of iodine. Steeping grains for extract brewing though, is only for the flavor of the grains its self, so time and temperature are not as important as if full grall brewing. Boiling times however, vary depending on what your trying to do. One hour is customary for proper bittering hop extraction, protein coagulation etc.... the boil can be extended for increased evaporation (producing a more concentrated wort, ie: stronger beer), more caramelization, or a more bitter beer (90 minute hops)

Yes, I'm extract brewing, should have said that, sorry. Thanks for the response, that makes sense.