A proudly thrifty travel companion once confessed that if he could pay $10 to fix a problem, he always did. The relief from unnecessary stress was worth the cost. His thinking was sound. Saving a few bucks with a slow shuttle that makes multiple stops probably doesn't make sense when a taxi is available. Buy-on-board food is usually a rip-off, but it's still better than arriving hungry. And if you flew all the way across an ocean, it's worth paying the admission fee to visit a museum.
Timing also matters. One mistake many people make at hotels is that they tip too little too late. Acknowledge the doorman and housekeeper when you arrive to get better service for the rest of your stay.