[luckylion]

I don't think it's possible for the US president, they are limited to 10 years (two terms + two years if they were vice president and became acting president) which, afaik, is per life-time.

I agree though, it's not an issue, precisely because the German president has historically not acted partisan (even though he's usually a member of a party) and not be involved in day-to-day politics, so it's not too hard to find somebody that everybody can agree on. This may change if the office becomes more politicized, but I doubt we'll see somebody get re-elected after having paused for a term.

[notkaiho]

That's correct - a US president cannot serve more than two terms. If they were already acting as President for two or more years, they can only be elected to the position once. This was codified in the 22nd Amendment to the US Constitution.