Hi, after reading through this thread I'm still confuse about whether there's a need to use sealer and skim coat for interior wall or not? Are they supposed to be used regardless of new house or old house?

I was quoted 5K for interior only (exclude doors, door frame and grille). House is double storey intermediate 20X65 built up 1780 sqft, 4 rooms.
Not sure whether this include paints already or not but plan to call the contractor later.

Other than below questions, what other details I should get from him before deciding is this too expensive or reasonable?

Include skim coat and sealer (need for new house?)?
Include ceilings?
How many layers of paint (actually how many layer will be ideal for new house?)?
Can separate the quotation to workmanship and paints price, cause I want to buy my own paint?

I'm planning to have dark color feature walls in living room and all the bedrooms. Is this going to make the price higher?

So I should go for 1 layer skim coat + 1 layer sealer + 2 layer paints?
I'm going for matt finish Nippon Spotless.

That day I bought 2 can Nippon Spotless matt from Ace in Ikano Power Center, got 15% discount.

I think there's 20% out there but since I was buying 2 can 1L only so didn't want to drive around anymore.