Maybe you've been ignoring or putting off fixing your leaky hose bib for a while now... You've got it in the back of your mind to fix it when you have time, but it's sort of an "out of sight, out of mind" thing, and when you go inside, you've forgotten all about the outdoor faucet.
This can be a major problem for your water bill, since, obviously, it wastes a lot of water. It could be an even bigger problem for your basement, crawlspace, or slab depending on the severity of the leak. If the leak goes deeper than just a loose packing, it could be in your pipes, which could cause a whole mess of problems when you turn on the faucet for the first time this summer.
Why is this happening to me?
A common cause of a leaking hose bib is a crack. This is common if your hose bib froze over winter, and is caused by leaving your hose attached to the spigot during the winter months.
When you detach your hose from the outdoor faucet, the water drains out, releasing the pressure in the pipes. If you don't detach it, that water and pressure have nowhere to go.
If left attached during the winter months, the water in the pipes may have frozen, causing them to expand and crack. There isn't really a quick fix, DIY solution for this. In this case, your hose bib will definitely need to be replaced.
Why should I care if it leaks, since the faucet is outside my home?
Every time you turn on the water to this faucet, it's probably going to spray all over the place, and just get worse over time. Not only are you likely to get wet, but more importantly, you're going to be wasting a lot of water with this leak. Water spraying anywhere you don't want it to be going is literally money down the drain.
Even if it's not causing a larger problem or making a mess inside your home, the cost of not fixing a leaky outdoor faucet can really add up. Keeping this problem around will probably end up being more expensive in the long run than hiring a plumber to fix it right away.