I can't get my Draconian lemon lime to thrive. Its leaves always turn yellow and then brown and crispy until I have to pull them off. It's beside a west facing window which always has sheer blinds down. Room temperature environment. Pot has drainage holes. I don't overwater (as far as I know). I've closed the AC vent near the plant so it's not getting cold air. I've tried watering it more and watering less and it doesn't seem to make a difference. I want this plant to be healthy but I don't know what to do!

Your plant isn't getting enough light.

North windows in Canada 🇨🇦 are not all that great; the "sheer" curtains block most of the possible light, so that can be remedied by keeping them up.
I find this cultivar to be difficult to keep in good condition; also many that are sold are infected with two pathogens that weaken and disfigure them. Your plant appears to show symptoms of one.
It may be getting too much water or water too frequently.
They can be allowed to get bone dry to the bottom of the pot. Especially in winter go dry and stay there.
If it recovers it will be a slow process, taking many months. If it still has spotty leaves this time next year, replace it.

Iochroma, could you elaborate a bit? What are the two pathogens, and are they treatable?
Thanks!

@Ichochroma I just realized it's actually a west facing window. I assume that may change things?

hstokesdesi said: @Ichochroma I just realized it's actually a west facing window. I assume that may change things?

Yes, in that it is much better light than a North window; no, in that you must still raise the blinds so the plant can get some light.

MsDoe said: Iochroma, could you elaborate a bit? What are the two pathogens, and are they treatable?
Thanks!

There are no practical treatments for the home gardener; the nursery who grows them should be keeping them clean. Florida-grown plants are suspect; Hawai'i-grown ones are usually clean.
This form of D. warneckii shows the disfigurement very obviously, but many species of Dracaena are affected. Never buy a Dracaena with spots. Sterilize your tools after cutting an infected plant.

I struggled for several years with one of these, the pathogen theory makes perfect sense to me.