So I've already restarted Shippuden twice and I would love to continue watching, but I can't remember at which episode I left of. So here is what already happened maybe some of you might be able to help me out.
I don't know which of these was the latest, but maybe you could help me find the closest episode.
You are on the Kazekage Rescue arc. This arc spans between Naruto Shippuden episodes 1 through 32.
Since you have watched the episodes where Sakura and Chiyo face Sasori, which is around episode 26, you are probably somewhere between episodes 27 and 32
That is the Kazekage Rescue Mission arc.
According to the wiki,
the Kazekage Rescue Mission covers Chapters 245 to 281 of the manga and Episodes 1 to 32 of the Naruto: Shippūden anime.
To add, the fight with Sasori lasted from Episodes 20 to 27. If you have seen this, then watch starting at Episode 28. However, if you are already on the later part (where they already took Deidara's bird down) of the chase, then you should start at either Episode 29 or 30.
