That would not change my opinion of a candidate. The candidate himself/herself should decide this for his/her own. If age is an issue, you can also ask this for TRUMP.
However, it would be interesting to have. The last one-term president who declined to seek reelection was Rutherford Hayes in 1880 (not counting one-and-a-half-termers like Teddy, Coolidge, Truman or LBJ).
Didn't Biden say last year that if he'd run and win, he would only serve one term?
Just wanted to note on LBJ, as far as I know he did run, but dropped out early in the primaries after doing poorly.
Yeah, same with Truman in 1952.