Looking for some Thanksgiving Cactus insight...

Hello everyone!

As the title suggests, I'm looking for a little help when it comes to my Thanksgiving cactus. I've had this plant for around a decade now, and it has rarely given me trouble. Over the last few months, however, I have had several instances where large branches of the plant (where large is defined to be say sevenish segments) have just dropped off.

My first round of investigation made me think watering was the issue, but I'm not sure that is the case. Whenever I water the plant, I hold the pot over a tub that I use to keep a friendly moisture source nearby -- so there is no residual pool. I wait until the top of the soil is dry before watering again. My average watering rep rate is probably around once every ten days.

The lingering thought in my brain is that this guy needs to be repotted as it has been a long time, but... these plants like to be root bound so I'm hesitant to risk an environment change if something else is at play. I've attached a bunch of pictures of this plant with the hopes that folks far more knowledgeable on the subject might be able to discern something. I've definitely noticed some interesting colorations and textures, so maybe my plant is trying to tell me something and I just don't get the language.

One other possibility is that these fall offs have happened after fairly sudden weather changes (sudden snowing in Chicago, etc). I was wondering if a door draft might be at play. Either way, I'd appreciate any insight if there is any. Perhaps this just falls under natural behavior, but perhaps there is something more that I need to know.

Thanks for your time,
~Wing