Currently, we own 5 lights. However, rarely do I put all 5 into action. That doesn’t mean I can’t, but I don’t really need to because I have a general understanding as to how to use my lights. And that is always where I recommend photographers start when it comes to improving their ability in their craft. You don’t need 5 lights most of the time and a lot of the time you can get away with just one light so long as you understand how to manipulate that one light.
If you only have access to a single light, be it a speedlight or the sun then great. Get out a reflector and see what you can do. Learning to manipulate the light you have when you are lacking options to add light will only help you be that much stronger when the time comes when you do have more light options. If you can master a single light and really explore all the different ways you can utilize it then when you do go to add a light all that knowledge doubles over to that new light. In fact, every time you add a light after you learn something new with a single light you can utilize that knowledge on every light you add.
So, it pays off to learn how to utilize a single light in as many ways as you can.