Nearly all hotels in Europe have in house/out house laundry (they pickup/deliver, etc), in smaller towns or on weekends you may NOT have access to dry cleaning though. So again, some fabreze and an steamer/steam iron can sort out most things.
Now that I carry both I take clothes for half the days I'm travelling. If I get laundry/dry cleaning (that isn't a rip off that's a bonus)
Also suggestion NOT to take anything you think you may only wear once (exception to workout clothes, beachwear, and ONE formal outfit!) You will find that taking such items normally results in not wearing it even once.