One company I flew for kept one away from home for 18-20 days at a time living out of a rollaboard. Not being particularly accurately scheduled it was a bad idea to hand a uniform over to the hotel laundry to clean and press as they aren't open at 0200 when we tended to get the phone call to man up. There are pilot uniforms in laundries all over the planet gathering dust from freight crews that took the risk and never were able to pick them up.
We wore standard airline uniforms until the last hatch closed and the agent waved us off. Then rapidly switched over to whatever was easy to wear and maintain long term.
A 747 cockpit full of kimonos or track suits wasn't an unusual sight.
Best to switch over before top of descent though. More than one agent has been surprised by a crew that got too busy to change into uniform.