Noob Lord chooses which paint to use in the house

Why write this?

Because buying paint at Bunnings is super confusing. Buying the wrong paint costs you time and money. I have definitely bought the wrong paint before.

Buying paint at Bunnings is confusing:

Find out what you need before you go to Bunnings.
In Australia you'll probably be buying at Bunnings. If you go down to Bunnings there are rows of expensive paints and the paint you want is probably hidden in a very small section furthest from the paint counter. I think they purposely make it confusing to try and get you to buy expensive paint. If you ask for help you will be shown expensive paint and other expensive paint and be asked to make a choice!
The main problem is instead of organising the store by paint product type it is organised by Brand which is crazy. Bunnings don't do this with anything else. I am certain they do this to push the expensive paint.

Brands are confusing:

Bunnings sell Dulux, British Paint, Walpamur, Taubmans, and Spring. But Dulux, British Paint, and Walpamur are all owned by Dulux! I don't know who owns Spring. Dulux advertises British Paints and Dulux but there's no website for Walpamur. I don't think Dulux wants you to know they own all of them. Taubmans have different brands but they are all marked as Taubmans. For example they have Taubmans Tradex and Taubmans Trade Pro. You will find that 90% of the floor space is set aside for the expensive Dulux, British Paints and Taubmans non-trade brands. They also seem to price match each other, so when you compare British Paints, Dulux and Taubmans the prices are all the same. 
Not only do they have multiple main brands, but then the expensive brands have sub brands for example Dulux for ceilings have 3 brands, Dulux Ceiling White + PLUS Kitchen & Bathroom, Dulux Ceiling White Never Miss and Dulux Ceiling White. 
So it's just a massive sea of brands. This is another reason to stick to the Trade brands because the trade brands have just one paint per paint type.
Bunnings hide the value paints in a small section all together furthest from the paint till. You will have to look around to find it. You'll probably find Walpamur, Tradex and Spring together.
Why do they have all these brands? It's to make it confusing because they don't want to compete on price. As you can see below there's a big difference. If we take for example ceiling paint:

Brand	Price per litre in AUD
Dulux Ceiling White 4L	12.50
British Paints Ceiling White 4L	11.25
Taubmans Easy Coat Ceilings 4L	11.63
Taubmans Ceiling Paint 6L	4.50
Taubmans Trade Pro Celing	7.25
Walpamur Ceiling Paint 4L	7.25

Paint types:  

When you know there are only 4 paint types it all becomes super easy.

Interior wall
Ceiling
Undercoat
Enamel (Water based or Oil based)

Enamel is used for doors and skirting boards because it dries hard and should be scrubable. Which normal wall paint is not. This can be confusing because Dulux sell "Wash & Wear" paint, which is actually for walls and not really scrub-able. Enamel only comes in Gloss or Semi-Gloss. So you can't paint a door Matt!

Enamel comes in Water and Oil based. Water based allows you to wash your brushes up with water but only the expensive brands do it. The trade brands only do oil based enamel.

Water-based enamel paint	Oil-based enamel paint
Does not yellow over time	Will yellow with the absence of UV light (sunlight)
Offers a full range of colours	Offers a limited range of colours
Not always suitable for areas subject to harsh treatment. In my experience it dries soft. So it's easy to dig in a nail and muck up the finish. I think it's the reason you can't buy water based enamel trade paints. For this reason I'd avoid it.	Great resistance to harsh wear and tear, as oil-based paints are harder and abrasion-resistant
Comes in gloss and semi-gloss finishes	Comes in gloss and semi-gloss finishes
Not able to produce a brilliant gloss	Able to produce a brilliant gloss and extremely smooth finish
Not suitable for all window frames, as it can stick	Suitable on all window frames, as it will not stick

https://kraudeltpainting.com.au/water-based-vs-oil-based-enamel-paints/

It says that with water based enamels it dries faster and a second coat can be applied in 2 hours. That is not my experience and I had to leave the water based enamel for a day, but it was cold and damp.