[PJamo]

How many dancers are still there from the first series? Was Anton the last one when he switched from dancing to judging?

He was - the longest serving dancer now is Karen who joined in series 10 (2012). I think she's also at this stage the 3rd longest serving dancer in the show's history after Brendan Cole (15 series) and Anton (18 series before moving to the judging bench).

Not even Claudia was there at the start - It Take Two didn't start until series 2 and apart from a one-off when she covered for Bruce she didn't start hosting the results show until series 8, which inevitably made her the obvious choice for when Bruce retired (and there's part of me suspects it was succession planning when it was decided she would take over from him on the results show but I've never heard that theory confirmed).

It's just Tess, Craig and Anton who have been there from the beginning, and only those 3 plus Karen, Giovanni, Katya, Neil and Gorka - so 8 out of 26 hosts/judges/dancers - plus some of the musicians who have been there since before 2017.

The piecemeal turnover of talent definitely helps keep the show fresh yet also stable in a way The X Factor failed to do - it seemed like every year or 2 years on that show there was a complete overhaul of judges or insistence that the show was going  'back to basics'.

Even the set of Strictly gets subtly tweaked most years - oftentimes it's a slight adjustment here or there - so in many ways it's very much the same set as it was when it relaunched in 2010 then expanded upon when it went to Elstree in 2013 (I think).

Evolution, not revolution seems to be the name of the game to keep formats running rather than crashing and burning. Look at GMB's longevity versus it's predecessor's (or the aforementioned X factor vs BGT).