Weight training has many benefits. If you have been considering it but balking, you likely have multiple reasons for not getting started. One reason might be: you have no time. Well, if you have thirteen minutes, you can do a weight workout. As noted here, In a Hurry? Try Express Weight Training – The New York Times, you can get stronger no matter what. Of three groups tested for strength gain: 

One group was asked to complete five sets of each exercise, with about 90 seconds of rest between sets. Their total time for a session at the gym was almost 70 minutes. A second group was asked to complete three sets of each exercise, requiring they work out for about 40 minutes. The third group had to finish only one set of each exercise, meaning that they were done after a brisk 13 minutes. Each volunteer performed his given workout three times a week for eight weeks and then returned to the lab to repeat the muscle measurements. After the two months, all of the young men were stronger, a finding that, by itself, is beguiling, since it suggests that people can continue to gain strength even if they already are experienced at resistance training. But more interesting and surprising, the strength improvements were essentially the same, no matter how many — or few — sets the men completed. The men who had stopped after one set gained as much strength as those who had done five sets or three.

As with anything, your results may vary. But if you want to get stronger with the least amount of time put in, consider this.