First of all, the entire lower level remodeling process is easier because the foundation, ceiling, floors and load-bearing walls are all already in place. And, chances are, the plumbing system and heating and cooling system are already in place too. This makes it easier on your lower level remodeling company (and budget!) because these main parts of your basement are already there. There is no need to lay foundation, like there would be if you had an addition built onto your home.
Also, your lower level is a blank slate. You probably are not using this part of your home (other than maybe for storage), so your imagination is the limit! Do you want a home office or a guest room? A playroom for your kids or a home theater room? If you go with a guest room, you now have space for overnight guests to stay in. If you go with a playroom, your kids can play with all of their toys and you won't have to look at the mess if you don't want to.
Plus, your new lower level can offer a new level of comfort for your family. Your renovations will probably include new insulation, so this can make your basement the most comfortable part of your home. It can keep you and your loved ones cool in the summer and warm in the winter. And the new insulation from your lower level remodeling project could also help you save some money on your heating and cooling bills.
Your basement already offers a lot of space, so make sure you are using it! Basements and lower levels aren't just for storage anymore. You can really make your home uniquely you by tackling a lower level remodeling project! Depending on how big your basement is, you could have several different rooms. You might just end up with that home office and guest suite you always wanted.