I like to stick to one series so I can focus on it. Sometimes if I try watching multiple shows at once, one of them will become my main focus and i'll never get back to the other one.

I can watch multiple shows, but far too often I run into the same problem as you.
I have to make a conscious decision to force myself to not ignore one of the shows.

Since I started up Liveman, I haven't watched a single episode of Kamen Rider. I know I was in the middle of a two-parter but I don't remember a lot of the specifics of the first half.

That's why I only stick to one show at a time :lol

It doesn't help that lately I've been REALLY wanting to watch Hurricanger...but I'm not going to until I finish Liveman. Could be a while, I'm only on episode 10

I'm really enjoying Gokaiger so far. Taking a break at 46 to watch the Gokaiger vs Gavan movie.

I usually watch two shows at a time in three-episode sequences. I don't have a ton of free time now, so I am stuck on episode 28 of GoGo-V and Carranger, but usually I can pretty quickly plug through a show. I did that with Maskman and Liveman and was finished with both shows in like 3 weeks or something (with a regular watching time most nights). It works for some and not for others, but I understand the merits of watching only one show at a time.

I can watch multiple Sentai at once, I rewatched Jetman alongside Boukenger,Gokaiger, and Carranger(saw these three seperately) but obviously at a slower pace, and recently started a Zyuranger rewatch, mainly I couldn't remember much of these shows since I was completely cut off from Toku for a 2 year period(my fault lol).

I just watched the first episode of Zyuohger. Okay, not really, it was a 3 minute trailer, but I felt like it was the first episode as it has American Movie Trailer Syndrome.

Just watched Liveman 10. The episode was probably one of my favorite ones so far, but it was just a standard episode. I feel like I may have missed something though.. in the first two episodes, they were in the school as it got destroyed. The next episode mostly took place in a forest, if I remember correctly. After that, they end up in cities. Was there any sort of plot point explaining this that I missed, or did it just sort of happen?