I don't do room service when I travel any more. It took me years to get to this point, but now I just stick on the "privacy please" door thingie and leave it on for my entire stay. I only have room service now if I've got potentially smelly leftover containers filling up the trash, or if I run out of something critical like toilet paper. A few reasons:
1. As I mentioned in this post, I have a system for organizing all my stuff when I arrive at the room. It mostly consists of dumping all the toiletries in the bathroom shelf, plugging in my laptop(s) and ancillary cables, using every free hanger to hang shirts and other "nice" clothing (assuming that I'm traveling for something other than fieldwork and actually have something that I care about keeping unwrinkled) and piling outerwear so that it's easily accessible. It's not much to look at, but I don't like my system to be disturbed.
2. If I'm doing fieldwork or spending all day at a conference, certain items of clothing will get... ripe. Like socks and undershirts. Rather than tuck all the stinky stuff into plastic bags and letting them marinate for a week or more, I throw those items into the closet. I would prefer that the hotel staff not run into my pile of really dirty laundry unexpectedly.
3. I hate short-sheeted beds, and I need to have the edges of the blankets free to tuck between my legs*. So when I first get to bed, I spend some time yanking out all the sheets to my satisfaction. Likewise, I toss all the extra pillows off the bed and keep only the pillow that is sufficiently flat (or use my own). I don't need to re-do that every night.
4. Who washes their sheets and towels daily? Not me. I'm totally fine with hanging up my used towels and letting them dry. I don't need them replaced if I'm staying for a week or less.
5. Tipping in hotels can be a bit of a minefield. If I never use room service, I never need to tip anybody, right?
Most of my coworkers are similar to me and don't use maid service. Are we outliers, or is this common?
*My first bad case of poison ivy was between my knees when I was 8 or 9. My legs rubbed together while I slept on my side, and after a few days, the rash had spread to my inner thighs and was completely unbearable. Ever since then, I've slept with either pajama pants or the edge of the sheet tucked between my legs because I can't stand having my bare thighs touch while sleeping.