More than likely caused by the low light conditions.

That would explain why it began to decline after several months of winter. Unfortunately light is the one thing I can't change. I have some small spotlight grow lights, but I'm not sure of their quality and I can only run them when someone is home. Should I continue to care for it as normal and expect that it will get better in the spring, summer and fall?

Also, I read an article that recommended leaving yellowing leaves attached to the plant - something about allowing the plant to absorb more minerals. Does anyone have thoughts on that? I usually remove them only when they come off very easily.

Light levels can be sufficient for people to see but not for plants. So what you perceive as daylight is longer than what most plants would. Dark for them would be well before 4PM in your room.

I generally let leaves remove themselves, plants know best when they're not wanted. But mine are all outdoors so not a problem anyway. I haven't noticed vines replacing leaves where the originals dropped from. So the growing end of the vine will look better but further back the vine will still look bare.

I agree with the low light levels. One thing I would recommend is to spread the vines out more. That way, each leaf isn't competing with its neighbor for whatever light it is getting. Another suggestion would be to switch out your bulbs for some "daylight" compact fluorescent lights, or, even better, some "daylight" LED bulbs. LED bulbs are more efficient and can put out much brighter light for your plant(s), using less energy. I've switched out all of the lights in my entire house to LEDs and I'm still trying to get used to the brighter light, HaHa! It's done wonders for my electric bill as well. LEDs are very cheap now, and they most definitely save you $$ in the long run.

Watering once a week in winter may be too often.

Danielle; I've told my mom the same thing, she says it works for her plants! I actually water mine less than that, the once a week watering I mentioned in my post is what my mom does for her plants!

Question; could this be a symptom of the plant being rootbound? Should I unnoticed it to check or wait until spring to avoid disturbing it while it's already fragile?

I doubt it has anything to do with the roots being root bound. I was visiting my sister one day and went over to her friend's house. They had one that was absolutely huge, with so many vines hanging from it. I never knew that they could grow in so thick like that. I knew that the leaves can get much bigger in size, if they're allowed to climb something. But there's were all hanging out of just one pot, and each vine was just so long. I wish that I had pictures of it.

I would still have to say that it's a low light issue. It takes energy to sustain a large number of leaves, and if a plant can't photosynthesize enough of that energy, then it will shed "x" number of leaves in order to cut back on the amount of energy is being used by the plant.

Thank you! Your description of your sisters friends plant sounds like how my plant looked when I got it; some of the leaves were at least 6 inches across! I am still sad to see it lose leaves, but I understand why it needs to drop them. As long as the plant itself remains alive and healthy I am happy. I will continue to take good care of it. It has continued to put out new, smaller leaves even as it loses its older bigger leaves.

Oh wow!!!! No kidding! That's incredible, thanks for sharing! I hope someday my plants will be happy enough to grow leaves that big :)

definitely caused by not enough light! as far as watering - pothos is very good about indicating when it's thirsty. when i notice the leaves starting to droop a little, i'll give mine a nice shower and it perks right up. they are much easier that way than other plants. as far as removing the yellow leaves, don't force it but i've pulled off loose yellowing ones plenty and it doesn't hurt the plant at all. the vine won't grow new ones as someone else pointed out, but if it's not a tiny little plant a couple of missing leaves is much less of an eyesore than a bunch of yellow ones. if you're worried about nutrients/soil, you can always try top dressing it before you try to pot it up. sounds like you're way up north so best not to repot til it's warmer.

While I don't think this is your problem, are you actually watering with warm water? Or do you mean more like room temperature water?

When mine get like yours, I give a good haircut and repot. I prefer a denser plant. I water when the plant's soil feels dry, not on a fixed schedule because conditions can vary even inside. (Mom can do what works for her...lol.)