Of course a meter is always nice to have, but I think it's got more to do with the number of lights you're using than anything else, and for setting up the lighting ratios and balance.
With one light, a meter is a waste of time. Two lights, not really necessary. Three lights, you'll get very confused without a meter.
The other thing is how you like to work. A lot of folks have just one or two basic set ups, and once you've sorted that, then you'll know what to do without a meter anyway. But if you like to try different things, or need to set up in different locations, a meter will get you on the money much more quickly.
The other thing is I never use a meter to set the final exposure - set the ratios, yes absolutely, but for the actual exposure I work off the LCD/histogram/blinkies.