I was asked which is better, few rules that are consistently enforced or many rules with intermittent enforcement. You could just as easily add many rules that are all enforced, but that would be exhausting for the parent and the child. This is an easy one to answer but one within the impelementation gets difficult.
Few rules that are on the things that are most important and that are broad enough to cover a range of situations. Rules that concern the rights of others, safety, concern for property are important and things that children of all ages (2 and above) come to understand. Other things fall into the category of things to store away for discussions such as at bedtime, dinner, a family evening together. Parents have a tendency to try to "fix" children's behavior through establishment of many rules. Years ago this was viewed as an attempt to "civilize the child." Sometimes parents can find a variety of ways to put everything the child does into those three categories. Don't over do it.
Once children are about five you can even start periodic conversations about what rules they think you have for them that they like and what ones they don't like. This brings out an opportunity for both discussion (listening and sharing) as well as reflection on what aspects is the child ready to take over for themselves rather than you being the monitor. Remember that this will not mean at any age the child will no longer do what "bugs" you, but just that the day-to-day management of that issue is being shifted to the child.