My colleague works after hours and over weekends for no additional pay, and I’ll likely be his replacement. My work ethic is 100% effort when in office and 105% if necessary, but I plan on drawing the line for myself if they try to transfer all these responsibilities to me in the future. I’ve encouraged him to speak up about the issue, but I’ve only been working here for 4 months and it’s my first job so I don’t want to rock the boat too much. How should I make it clear that I won’t be working extra hours when that time comes?