Currently working on this interior, This photo was rendered at 1500 samples, usually more than enough, but still has alot of noise, especially in dark areas. I have multiple importance switched on in the world tab, and i have the clamp direct/indirect on, any tops on how i can decrease this without having to change the scene?
Have you tried using the Denoise feature from Render Layers ?
https://docs.blender.org/manual/en/dev/render/cycles/settings/scene/render_layers/denoising.html
Well, I’m working on interior as well. Dark areas are pain in the a**. I use minimum 6000 samples plus denoiser for each render, and still in dark areas I can see imperfecions. 
If you don’t need 100% unbiased renders, you might consider trying the AO Bounces under Simplify. Just make sure to set the bounce number over 2 or else it becomes obvious.
Also, if you do that, you’ll want to experiment with your AO distance.
I’ve found that interiors render much faster and with less noise, but if you set your AO distance too short, or bounce number too low, some areas can look too bright.