Don’t underestimate the power of a new showerhead. Give your bathroom a spa upgrade for less than $100. Bonus: If you buy one labeled WaterSense, you might trim your monthly water bill. (It uses 20 percent less water than the industry standard.) OK the swap with your landlord, or store the original to reinstall. Try Delta’s In2ition FiveSpray Two-in-One Combo Kit, from $68; homedepot.com.