Should I open a credit card for my new multi-family business?

[Harry Williams]

I am just starting out with a partner, and we plan to purchase a ~20 unit apartment building. We have a business checking account set up with checks and debit cards, but do not currently have much monthly expense outside of email provider and legal fees (one-time fee). I am hesitant to open a credit card as there is an annual membership fee. 

At what point do those with experience recommend opening a business credit card in addition to checks and debit cards?