The number of burners your grill should have will depend on two things:
First, it depends on the size of your space. As should be expected, more burners mean a larger grill, so you will want to ensure that your space is large enough for the number of desired burners. Most owners manuals or line drawings will provide you with details on the dimensions of the various grills' configurations.
Second, it depends on how much food you plan on cooking at one time. If you're only planning on cooking for intimate groups, a close knit friend circle, or your immediate family, a smaller number of burners will do fine. If you're someone who likes to BBQ for large gatherings, you'll probably want to upgrade to more burners in order to cook enough for everyone.
