If you've decided to retire in your present home, there are various things you can do to the home particularly if you don't need to remodel.
Do you have rooms that aren't being used or are under-used? Then, you may wish to change their purpose. You can take a spare bedroom and turn it into a home office, exercise, sewing or hobby room, for example. Other options are a playroom for grandchildren who visit frequently or a media room. If the room is next to the master bedroom, you might even remove the wall (or just add a door) and make a master suite.
Another option for that unused space is to create an accessory apartment. This is a private living unit that has separate living and sleeping quarters, kitchen (or kitchenette), and a bathroom. It is sometimes called an "in-law" suite. An accessory apartment can provide additional income (and often a nearby supportive presence or care-giver) without having to share your home with a "roommate." Be sure to check your local zoning laws, however, before beginning your remodeling to make sure that your planned "in-law" suite meets your local codes. In some residential areas, for example, zoning laws prohibit adding an "apartment" with a kitchenette, or a separate "rental" unit, but allow a bedroom-bath "in-law" suite.