Once you've established a good, solid running base, it's definitely a good idea to complete a half marathon (13.1 miles) before a full marathon. Many runners, from beginners to advanced, run a half marathon during their marathon training as a confidence booster and a way to figure out their marathon goal time. It's helpful to get that kind of long distance race experience because you'll feel more physically and mentally prepared to go the marathon distance. Finding a local half marathon is not too hard in most areas, and you can fit into your marathon training schedule at any point after you've reached 10 miles for your long run.
More Frequently-Asked Questions About Marathon Training and Running