How many mark your carpet with tape?

I think it is a good idea. Haven't done that, but, good idea.
I use my rug's pattern to mark my drum's places, but only I know the placements. Tape would allow my bandmates to help more.
I dont mark at home. When I was gigging, I used a fat sharpie marker to mark my rug. Nice and thick lines so I could see it easily. Sharpie doesn't fall off. If you change setups, sharpies come in different colors.

Once I do the floors in the room, I want this carpet to set up on:

Not using it at the moment, but i used a Meinl rug with Meinl velcro strips. Works like a charm!
I used a fat sharpie marker to mark my rug. Nice and thick lines so I could see it easily. Sharpie doesn't fall off.
Same here, and just for my touring kit, whose sizes and positioning haven't really changed in almost 30 years! 😮 I've been using a black rug for a few years, and it's 'spiked' with a silver paint pen.

If you change setups, sharpies come in different colors.

That's an excellent idea!
That's pretty awesome! I'm going to go check that out!
This is the rug that i have and these are the velcro markers. The markers stay on the rug when you role it up and very easy to adjust as well. I use the round markers for the floor tom legs and the bass drum legs. The rest is to mark stands and pedals etc. The markers also work on the Rockbag rug i have too.
I use a square piece of marine carpet.

It's dark blue and low profile.

I use a rack so I use a silver colour sharpie to mark where the legs go, I outline where the pedals are and the bass drum spurs too.

The rack is marked as well so I know where each cymbal and tom brackets go.

It is hard to remove the markings if I create a new set up, the idea of different coloured Sharpie markings is a BRILLIANT idea...... never thought of that.
I try to avoid anything making my life easier or consistent, so there's no way I'll start using tape to mark anything.

My problem I use 3 different kits with two different sets of cymbals. I seriously should start doing this though.
I love it when I'm gigging a lot. I use black duct tape cut into narrow strips, it sticks to carpet well.
I don’t find the necessity, once the bass drum is set in the middle with the spur just by the edge of the carpet, everything else falls in the right place. I never find the need to be precisely the same position. Otherwise I would also need to mark the height of each cymbal stands and so for forth.
I can quickly tell if something isn’t right just by visualising.
Though I often gig, IMO, it’s overkill for my use.
Two things need to be set as precisely as possible: seat height and snare angle and height.
Its been noted but I used a sharpie when I had my Stealth Racks, It made set up so simple. Tape can peel after a while, the sharpie was there forever.
I only use tape to tell me where the BD spurs are supposed to go. The rest of the kit is pretty easy to dial consistently from there (1U/1D, 2 crashes, 1 ride) . But since we use a custom circular riser and real estate is at a premium, I've got to place the carpet at exactly the right spot on the riser and the kick at exactly the right spot on the carpet, otherwise mic stands placement can become a challenge.
I don’t have a picture handy but I’ve used the same drum rug for the past 8 years or so. It’s one of those rubber on the bottom with crap-tastic carpet on the top that is sold for $20. It’s only like 6 foot by 4 foot and as such only one of the throne tripod feet sits on top of it. I use dark red gaff tape to mark positions on it for everything except the throne. I did end up putting a double layer of black gaff tape where the BD spurs contact the rug because it was getting holes and tears there. (I extend to the BD spur spikes for extra grip.) I choose the dark red gaff tape so I stood a snowballs chance in hell of actually seeing where the positions were on a dark stage, but I wanted a color that wouldn’t be obvious or distracting if the stage was illuminated. (Like blaze orange or fluorescent yellow.)

That rug has taken a beating after being used 500+ times but I’m still using it. The gaff tape does come up in direct sunlight when it’s 1000 degrees outside and the Amazonian humidity makes you rethink your life’s choices, but if I just press it back down with my foot when I’m packing up, it re-adheres to the carpet.