How much contingency should a renovation budget have?

https://jwac.asureforce.net/Redirect.aspx?PunchTime=&LoginId=&LogoffReason=&redirecturl=https://nyc3.digitaloceanspaces.com/us-east-1/capitalregionbuildreport/uncategorized/how-long-does-an-office-fit-out-take-in-albany-ny.html

Clifton Development Group on why 10 to 15 percent is realistic in an existing building, and why 3 percent on a 1960s Capital Region property means change orders are coming.