Any clue when this becomes relevant?

@JussiVilleHeiskanen Lagarde's term runs until October 2027, though there have been reports she may step down early to let Macron and Merz control the appointment before the French elections in April 2027.

Media discussion about succession is already pretty active, see e.g. https://www.politico.eu/article/the-insiders-guide-to-ecb-musical-chairs-christine-lagarde/