Sealing is required out here in the land of perpetual sun. We have, it seems, 380 days of sunshine and 15 days of torrential downpour every year. Using my infrared thermometer, concrete gets to 165 F and blacktop to 154 F (concrete has more mass and density therefore it doesn't shed the heat as asphalt will). The intense sun actually "cooks" the top layer of black-top and then the sudden rain will wash it away.

Heated sealer flows better and will seep into minor cracks but it's heated mainly for ease of application. The roll-on stuff from Ace Hardware seems to work as well if you apply it in the mid-afternoon of a sunny day. It's a nasty job and I'd suggest having a pro do it. They can whack it out in a couple of hours and usually for about the cost of the shoes you have to throw away and the carpet/furniture cleaning bill for removing those spots you didn't realize were on your pants.