It should be base on your choice, what is want is what will determine the outcome of your decision, you can use an address a many times as possible either in making or receiving payment, but some people may just decided to use multiple addresses each time they are engaging in receiving payment, this now also depends on the source you are receiving from, use a single address if the means sending you payment is fixed and steady (constant), use different address whenever you want to receive payment from different sources on an irregular basis and if you're privacy minded.