Of course not. The whole reason many of us became entrepreneurs in the first place is to minimize the amount we have to work.

I, for instance, spend maybe five hours a week maintaining the little web empire that's bringing in enough to live comfortably on. Sure, there's always a period of intense building at the beginning of a project where you can find ways to occupy yourself for upwards of 40 hours in a single week, but if you choose your niche well that period doesn't last long, and soon you're on to the marketing phase which is measured more in calendar time than IDE time.

Naturally, if you're the sort of person who works 80 hour weeks, you'll find a way to build a business that requires 80 hours of your time each week to stay out of crisis. On the flip side, if you're the sort of person who prefers month-long periods of idleness on tropical beaches with occasional email checks to verify that your business is still running itself, that's entirely doable as well.

Tough one. Few suggestions:

#1 Track your time for few days and categorize each minute of what you do. How many of them are productive and pushing your business forward? In most cases 20% of your time is bringing you 80% of the gains. Pareto principle.

#2 Are you focused on few important things or your focus is spread to too many things? In most cases it is better not to do somethings rather than do them badly. Focus on the 20% from the point #1.

#3 Do you get enough rest and fun? If you work too hard you are less productive and with exhaustion it takes you 2-3 times longer to complete tasks than that you would do with enough energy/rest/focus. Have at least one day off (or 8 consecutive hours) a week and try to relax few times a day with one bigger break and several smaller ones.

It all depends on what you want to get out of your business. You can definitely structure your business in a way that minimizes the amount of time you have to be involved. This can be through outsourcing, delegation, or even just by picking a business model that requires less hands on involvement. If you haven't already, read 4 Hour Work Week. http://www.fourhourworkweek.com/

Look into 37Signals, specifically David Heinemeier Hansson. They're always giving speeches/talks about running a business with reasonable work hours.

You don't have to work 80-90 hr/week. But if you don't, then you probably aren't an entrepreneur.