You will want to set some options to control how providers enter information for the category. These can set on the "Edit category" page which you get to by clicking the "Edit" link from the page that displays all your categories (Admin > Settings > Categories). I'll continue with the "Included bills" category example to illustrate some of the options you'll need to consider.
Is the information essential for students, or just nice-to-know or only relevant for certain listings? Included bills would most probably be a required category because most if not all students will need to know this to determine their living expenses. An example of an optional category might be whether smoking is allowed in the house - it's not a big deal if providers don't specify this information. By making some categories optional, you make it easier for providers to complete the form -- they can skip fields that they don't think are all that important. If you have more than 5 or 6 required categories, you should consider making some of them optional so that the listing form doesn't become a challenge for providers to complete.
Can the answer to the category question have more than one answer? The "Included bills" category should allow more than one answer (bill), or one, or all, or none. Rather than create values for each of the many possible combination of bills, "Electricity", "Electricity & Gas", "Electricity & Internet", "Electricity, Gas, Internet & Phone" etc., you can tick the "Allow multiple selections" option and you only need to define the 4 possible category values: "Electricity", "Gas", "Internet" and "Phone". This also makes it easier for students to search: they only have the 4 possible values to choose from.
Note: for a multiple selection category, you can choose more than one value by holding the Ctrl (PC) or Command (Mac) button and clicking values.
Do you want allow providers to enter other values besides the ones you specify? For the "Included bills" category, it's possible that some providers will include other bills in the rental price, such as cable TV.
You have some decisions to make here: do you want to only allow the most common bills, do you want to try to specify all the possible bills, or do you want to specify the commonly included bills and allow providers to enter others? If you choose the last option, you can tick the box to "Allow users to enter other values".
Keep in mind though, that when providers enter "other" values, they're harder for students to find in searches. Try to specify the most commonly used values to make things easier for students, and providers too.