How much you will need a rental car depends on how you are getting to Hartford, what you will be doing in Hartford (will you be visiting the suburbs) and where are you staying?

If you are arriving by plane and flying into Bradley International Airport there are numerous rental car agencies right at the airport as well as the CTTransit Busses which will bring you right into downtown Hartford.

If you are arriving by train and are planning on staying just in downtown Hartford during your trip you dont need to worry about a car as you can walk to everywhere you need to go and if there is bad weather there is the free of charge downtown circulator bus called the Star Shuttle and there are cabs.

If you are planning on visiting some of the sites in the suburbs such as Old Wethersfield, the Science Center of Connecticut, West Hartford Center, etc. a car would be worthwhile as there is bus services to some places but a car can be more reliable

All of Hartford's hotels have some sort of parking arrangement (including the downtown ones). The downtown hotels have parking usually in attached garages or lots that is at a daily charge. The hotels outside of downtown Hartford and in the suburbs have surface parking lots that are usually free of charge. If you are planning to drive to sites in the suburbs as well as sites in other areas of the city such as the Mark Twain House all of these places have designated parking lots of areas.
 

There are a number of taxi and limo companies that serve the greater Hartford area.

To catch a cab in Downtown Hartford: (1) If you see a cab on the street they can be hailed down as in any major city (2) If you do not find a taxi you can call on of companies to request a cab (3) Have your hotel call a cab for you (4) Head on over to one of the areas where cabs congregate (see below)

Places to Find Cabs: One of the first places to look for a cab in downtown Hartford is Union Station which is the main Bus and Train station in Hartford and so out front there usually a number of cabs. Other places to try include the entrances to the Connecticut Convention Center and Marriott Hotel (PICTURED BELOW), Goodwin Hotel and Hartford Hilton Hotel