For starters, you'll have to contend with high electricity bills, especially if you're unwilling to try offbeat hacks like spreading yogurt on your windows. Well, to make the right decision, you must determine your AC's age. If it's younger than 10 years, repairs make the most sense — in almost all cases. But if it's approaching its 10-year anniversary or has surpassed this threshold, it might be time to replace this major home appliance. There are also other factors to consider, like your air conditioner's energy efficiency and the type of refrigerant it uses.