I searched through the forums and found no conclusive answer, so I'm effectively asking a repeat question.
In the corebook the spells Seven-League Stride and The Leap of Homecoming (ArM5, p.135) don't mention requisites for bring what you have on you (such as clothes, or tools, or things you picked up). And indeed, the ruling for Target Individual that "clothes on a person or moss on a boulder are part of the person or the boulder for these purpose" would support this (ArM5, p.112). However, another ruling (which I found here) mentions "Herbam and Terram requisites that allow a spell to change a clothed man into a bird" (ArM5, p.114) would imply they are needed?
This is further complicated by contradictory rulings for two spells that are essentially the same; CrCo15 50 teleportation spells. Wizard's Leap (Houses of Hermes: Sociatas, p.36) says a requisite is required, but Retreat into the Shell of Shadow (Magi of Hermes, p.131) doesn't mention any.
And that not even getting into how only Seven-League Stride requires a Finesse role while the others don't.
So does combat teleportation require a "feat tax" or not?
The conclusive summary of the issue is in Transforming Mythic Europe p.107 box New Guidelines for Instant Teleportation: Instant Transportation and Requisites. It starts with:
Ars Magica Fifth Edition does not specify whether casting requisites are needed for instant transportation, and this may be left to the interpretation of the troupe.
But it makes a suggestion later:
The view taken in this chapter is that since Rego Corpus spells move the body, anything that the body is wearing or carrying is moved as well. Living creatures cannot be transported without requisites, except for familiars (if they are carried), ...
So this is left to each party's discretion. With both of my gaming groups, we chose to take the harsher view that the mage needs the requisites to teleport non Co materials along (except for the talisman, for the same reason as the carried familiar).
This encourages necromancers to actually dress like the part, with human leather robes and belts, bone buckles etc. The ReCo mage in the saga that I ran had the creepy leathercrafting grog bring back the bodies of three dead bandits that the party had killed and fashion the outfit for him.
... which is less harsh than the view taken by my troupe, simply because we wanted to limit teleportation, but not remove it entirely:
Requisites required. There are no freebies.
No, not Talismans, nor Familiars either.
I approve of this. (The familiar part never came up as my saga ended before anyone got around to binding one.)
I do think that too much teleportation becomes problematic, and it takes away from the sense of "distance" in a campaign. I realise that this is a tangent, but I think that the Song of Ice and Fire did well in having Brienne travel slowly seeing the land in the book, whereas the final seasons of the TV show just had people teleporting to wherever it was dramatically appropriate.
To go on a bigger tangent: I did struggle in one session, as the players decided on a whim to travel to the Domus Magna of Ex Misc in Wales, from the Rhine Gorge, so that one of the PCs could register his house change (despite a plot-hook to do the same in nearby Picardie or my introduction of Tytallus coming to recruit the mage). I don't like glossing over such a journey, since it was almost a full season, but having nothing planned, the whole trip felt flat, for lack of a better term. The necromancer was gathering and labeling stones from places he went, so he could go back and forth, but he didn't go overboard.
IMO if this is your viewpoint, then you are probably better off houseruling that in your game hermetic magic has not invented teleportation.
To me all of these restrictions put on teleportation feels like an attempt at shadow-banning it, by saying: yeah sure you can teleport but you better be prepared to have extremely high scores in Rego and a whole bunch of arts, which we all know is next to impossible to get in a realistic timeframe (i.e. within the timeframe of the current saga).
To be clear I do think that you raise a valid criticism of teleportation. I dont necessarily think that it would pose a big problem to allow teleportation in every saga but there certainly are sagas where it would break the flow of the narrative.
The thing is, I'm not against teleportation as a whole, it can be nice to just help smooth things and just have things happen without requiring a season/adventure. While in the early game, I like the bootstrap feeling, I think that some things are fine being handwaved and done in fast forward. I was explicitly warned by a good friend who'd run an ArM saga some years ago (which included two of my players) that his saga had gotten out of hand once the party just started constantly teleporting.
By the end of my saga, the party would organise things smartly: send the companion on horseback wit the mage's stuff to [location] with a time schedule, and at a set time, the mage would (be) teleport(ed) and then that was a quick adventure which could avoid the 10 days travel limit. But it also means that the necromancer was not just teleporting daily from Germany to Wales or anything like that.
In small amounts, I think that it can be good to accelerate play, too much risks being a mess. The dose makes the poison.
And the Talisman is even more of an extension of the mage.
My campaign has a House rule where the mage's casting Sigil can influence how much "minor" stuff can be dragged along in a teleport. Sort of like a Sympathy, and even an Antipathy.
For instance, if the mage with the Sigil of a Celtic Knot ever learnt teleportation, he would find he could carry a lot of macrame/lace/knotted stuff. But something without knots, like a bearskin cape would be left behind.
Really, it's about what sort of stories your troupe want to play.
We've had a lot of use out of traveling and events that has happened during travels. So we wanted to restrict teleportation. Currently, we see a lot of action against the Mongols, just beyond Transylvania, and one character can simply teleport back and forth, thus avoiding (almost) all of the hardships but also bonding less with the other participants.
If we were playing pure politics, we could easily switch to the most liberal possible interpretation ('Feel free to bring anything within R: Personal!', which incidentally excludes a number of possible familiars and options for Talismans), thus getting a situation in which location is almost irrelevant for most magi a decade out of Gauntlet.
I believe this would lead to a very different Order, but that's just my take.
In the end, I'd argue that the best option is to discuss things with your troupe and find out what you as a group want to see.