From a credit card perspective, actually, you don't even need the house/flat name/number. As you can see easily on the basecamp paid signup page, all you need i

From a credit card perspective, actually, you don't even need the house/flat name/number. As you can see easily on the basecamp paid signup page, all you need is: First/Last name Card number Expiry Date Billing Zip The rest of the fields on https://signup.37signals.com/basecamp/Plus/signup/new https://signup.37signals.com/basecamp/Plus/signup/new are unrelated to billing. Worth noting that those extra billing fields like address and all that help cut down fraud (as well as signups...) so if your business is not b2b and relatively fraud-free, you probably should keep the extra fields for anti-fraud checks.