give somebody an inch

give (one) an inch and (one) will take a mile

If one makes concessions for someone, that will embolden that person to take further advantage of one, instead of being content with what they have been given. If you let the kids stay up later on the weekends, they'll want to do it all the time. Give them an inch and they'll take a mile.See also: and, give, inch, mile, take, will

give somebody an ˈinch (and they’ll ˌtake a ˈyard/ˈmile)

(saying) if you say yes to somebody for a small request, they will want much more: I said Joe could borrow my car occasionally, and then he started to borrow it every night! Give him an inch...!See also: give, inch, somebody