Okay, this is something that is never talked about with homeowners. I try not to push too hard, because to some people it might seem like a ploy just to get more money out of them, after an already pretty expensive project. But I always try to be honest in that besides cutting in expansion joints, sealing your concrete is the best thing you can do to keep it lasting and looking great for years. It's super simple so if you don't want to pay for it, I believe it is something most able body homeowners will be able to take care of themselves. It really just like painting a wall, just roll it on the concrete with a paint roller and DONE. And yes, sealing SHOULD be done every couple of years to keep it lasting longer, but at the very least it should be done after its poured and cured. There are plenty of reasons why sealing your concrete is important. Like for instance….you know if you live in the midwest I do, there are many elements that can ruin perfectly good concrete. Winter alone is harsh on everything, but then there is the extra salt, dirt and sand that will inevitably, end up on driveways and probably sidewalks. Which at first doesn’t seem like it’s doing anything and you think “concrete must be stronger than salt” But over time, and especially during the long winters, the chemical reaction will absolutely cause damage if it’s not protected.
Another thing...I will ALWAYS, no matter what, suggest and recommend sealing your concrete if you will be working on your car or anything like that. Motor oil penetration is something that would be smart to seal against. Power washing a sealed concrete driveway is much more satisfying!
Mold and weed growth is my third and final argument for the na-sayers. When your concrete is nice, new and fresh, you probably won't be able to imagine it looking any other way. But mark my words, over time, when you are driving on, playing on, sitting on, mowing around, working on any concrete, you will eventually see mold growth and most likely weed or grass growth in the cracks. BUT, there is hope. When you seal your concrete every couple years, you protect it. And even if those kinds of things are not much of a concern for you, you are able to protect against it. And then you won’t have to worry about it. However, I do get a lot of satisfaction when I power wash that stuff off an old concrete slab that never was sealed and protected. But that is just a side note. Anyways, if a contractor asks you if you want to seal and protect your new concrete patio or driveway, just do it. : )