Karla......WOW!!!

Your Dracaena marginata is huge. Soon it'll reach the ceiling. Hope you have another spot with higher ceilings.

This is how I grow mine. In summer, my marginata is grown like a tropical...during winter, it's cared for as a succulent.

Did you mention the material of its container? Clay, plastic?

Watering shouldn't be done by schedule.

There's two ways to test soil. Insert a long, thin stick deep within soil, to the bottom. If stick comes out clean, without soil/mud, give it a drink.
If stick comes out wet/muddy, don't water.. Re-test 4 or so days later.

The second way to test soil might be more difficult since your tree is gigantic.

Lift the entire pot. lol.
I weight 110-119lbs, depending on time of year..when I worked at a plant store, I lifted trees twice my weight. It was a 'x'itch lifting ceramic, self-watering 20" containers.

If the container feels light, it's probably dry. The thing is, you'd have to check weight after watering to compare.

I wouldn't repot yet. Wait until spring. For one, it'll be less messy if done outside.

I don't know your location, but here in IL, Dracaena's slow down growth this time of year.
Another reason not to pot.

'Some of the tips turned brown and dry.'

Did the previous owners keep marginata in or outdoors?
It's possible leaves browned and/or dried because it wasn't used to sun.
Even if your tree was in shade, it probably got more light than accustomed.
Also, being outside, Dracs need more water. I'd have used at least 1-gallon per drink.
More, if roots are tight and water runs through.

Which direction is window facing?

Anyway, your Drac is beautiful..can't believe you found it on Craigslist. I'm afraid to buy from CL's since the movie came out..lol.

Good luck, Toni

Thanks for the response! I donâÂÂt know the movie but I think we had a craigslist killer in Philly.
The window is North. They were on a deck facing west for half the summer. Lots of sun. The family I bought them from kept them in the yard during summer but it was a shady yard. I thought the water comes out quickly for a big container (plastic terra cotta look planter 22 inches) so the tight roots you mentioned are probably the case.

I will be posting many more questions. Lowes discounts all their ugly/dying stuff so I have gone on a few sprees.

Phillip Markoff was jailed and committed suicide in a MA prison.
I didn't know there was a second or copycat Craigslist kller
Yikes!!

See how your marginata does in the north window. It 'might' need a brighter window during winter.

Post away. That's one reason we'e here. To ask questions, give advice and look at others' plants. Toni