Power Rangers had gotten berated in terms of episode count. Here's what I think:
MMPR had three seasons, 155 episodes because it was such a monster hit. Saban would have wanted it to end after a year but demand was too high to do so plus the opportunity to earn more came in so while most costumes remained, zords were changed. Also, only Dragon Ranger's costume was removed and came in Kibaranger's costume for Tommy (strangely the child Dragon Ranger later played Kibaranger). However some disadvantages do happen in an overextended series- there will be a LOT of jump the shark moments like how Jason, Zack and Trini left altogether for the second season and later, Kimberly which for me ruined the chemistry of the whole show because she and Tommy were so cute together. In short, this is way longer than Goranger (the first Super Sentai back in 1975) which had 84 episodes and Kamen Rider the First which had 98 episodes.
Later the problem of being too short came which was during the Bruce Kalish seasons. They were rushed so none of the cool concepts like the Corona Aurora was given much room for development. It only had 32 episodes. This lasted until Power Rangers RPM. This means it's three episodes shorter than JAKQ, the second Super Sentai series.
I think it's time to really put a balance of the number of episodes placed in the series.