Garden hoses get twisted, kinked, get left out in the heat and the cold, and even get run over. Even the sturdiest hoses can spring a leak or develop a split. If your hose splits, don't throw it out; it can be salvaged easily and inexpensively.
Use the craft knife to cut the hose at each end of the split section. Dispose of the split and leave the two hose pieces in the sun to dry and soften.
Purchase a hose repair kit at a garden center or hardware store. Be sure to buy a kit made for repairing center hose sections, not ends. The hose kit will be metal or plastic, and will consist of two pieces, one for each cut opening.
Slide each piece of the hose repair kit into a cut end of hose, then join the two new fittings together. Wrap them securely with plumber's tape.