I'm a little hazy about what to call the hotel employee who takes my luggage to my room and shows me how things work. The term used to be "bellboy," but that's probably politically incorrect nowadays, and I wouldn't want to demean anyone.

I'm not crazy about availing myself of his services, but sometimes I can't get out of it.

Anyhoo, my question is how much shall I tip this person, who carries my carry-on sized suitcase to my room?

The term would be "bellhop or porter". There have been a few times when the porter has taken the luggage up to the room while we were checking in and is gone by the time we arrive, which is always interesting, but normally, we tip 1€ to 2€ a bag.

In the case of the missing porter, the concierge has show us to our room, and he/she gets the tip.

I don't normally tip if I can't get out of it (i.e. The hotel insists) and that's happened a couple times. I tip more like 3-4 if I genuinely needed the help, which is pretty rare, but when it happens it's because we have excess luggage.

"Bellboys" are rare these days except in 3

"Bellboys" are rare these days except in 4 and 5-star hotels. Normally, if your luggage is not huge, you can make it very clear that you will be carrying it yourself. If they rip it away from you and carry it anyway, I would consider it a point of honor not to tip them. In Europe at least, they receive a living wage without tips.