As someone that works out 4-5 times a week, yes, they are necessary. The reason I prefer a gym is simply because I don't have the room in my home for all the equipment I prefer to use, and all the different pieces are expensive. I don't use any services or other classes, so I look for gyms in the range of $20-$30/month. Cleanliness and quality of equipment are huge regarding differentiation. Another factor is the gym etiquette of other patrons. I prefer 24hr gyms because I can always get a workout in despite my changing schedule. Hope that helps.