People often use large public storage spaces for common events in their lives, such as moving their furniture or other belongings from one place to another, or holding onto estate items until an auction can be held after a loved one's passing. However, you can use smaller storage units for more everyday hiding purposes. Safer than hiding things at home or at work, using a smaller storage space to keep something a secret can come in handy when it comes to storing two specific types of items.
Smaller storage units are fantastic spots to store gifts. Birthday, anniversary, graduation, and other event-related gifts could be stored for safe keeping and secrecy. Hiding a gift inside of the house is risky because someone who is actively looking for it may find it. Worse yet, something that was supposed to be a surprise could end up being stumbled upon while someone is cleaning. Either way, the gift-giving aspect is marred because the person receiving the gift already knows what's coming.
Hiding the gift at work can be tricky depending upon what type of environment you're in. Will someone find it and think it's for them by mistake? Could it be crushed, overheated, frozen, or otherwise damaged (for instance, if you work in construction or mining)? Storing it in the car holds the same level of possibility of being accidentally discovered by someone who lives with you or shares the car with you. Also, if a gift is placed in the car, the car itself or the gift specifically could be stolen. That's on top of the fact that leaving a gift in a car could mean it gets rained on, fried by the sun, or turned into ice by the snow.
Clearly a smaller storage unit is the best option for storing gifts. You'll be the only one in your household with access to it, it can be placed in a climate-controlled environment, it will be secure from thieves, and it is in virtually no danger of being damaged or destroyed.
Public storage units are also helpful for keeping personal or special items separated from nosy adults and curious children. Your expensive baseball card collection is safe from sticky fingers. Your will is safe from prying eyes. Imagine a loving spouse going on a diet that takes all the chocolate--your favorite daily treat--out of the house. Wouldn't it be nice to have a place to stash a few bars so that you can still enjoy what you love without unnecessarily tempting the love of your life?