If you need an office because you can't live together or if there are few team members and it would be more productive to work in the same room you can get an inexpensive office for less than 4 people for a few hundred dollars a month.
But when do you do that? Say you're in the apartment during YC. Do you get office space with the $80,000 afterwards? Or when you get $1 million in a series A?
If you are already in an apt then the need for an office space is minimal. But if getting an office space will improve productivity then when you get the $80k. In NC we have an 1100 sq ft office space to work closer together and pay $750 a month. It has increased our productivity by 5x. If the business is going to fail based on a $750 monthly expense then it's time to rethink the model IMHO. For us it went from building a SaaS in 6 months down to 2 months. Your mileage may vary.
