Usually a room needs to be repainted every 4 - 5 years. It should be done when there's as little moisture as possible. But because we'r talking about repainting indoors and usually rooms are heated moisture is not such big problem.

Notice. old paint becomes brighter with time

Step 1: Tools

Tools you'll need:
- 1x 1liter of diluent: nitro or synthetic
- 2 rollers with handles. Size: big and small
- 1x masking tape also known as crepe tape. Size: wide
- 1x plastic net for removing excess paint from the roller (don't know the translation)
- 1x brush. Width: 5 cm
- 1x scraper. Width: 5cm
- clean plastic or wooden stick to mix the paint
- 1x 20l bucket or a tray
- 2x rags
- sandpaper type P150 or more
- 1 week of daily newspaper and/ or special lightweight blancket
- 1x yogurt container

Mentioned tools can be bought in shops but you can use homemade tools just check that tools are clean. Rollers can be bought separately from handles just make sure thay can really spin freely. The bucket should be big enough to mount 'the net'. Also keep in mind the bucket will probably be scrapped after the job (!).

Dress and shoe something appropriate for the job because that too can be scrapped. If you will paint also the ceiling, you should use a cap.

Step 2: Paint

I suggest you buy waterbased paints because thay'r nature friendly, easier to clean and need one layer only (!). Important informations about the paint can be found on product package. Before you buy the paint you need to know:
- is it for indoors or outdoors,
- how much area can it cover,
- how many layers you need to apply and
- how much water you need to add.
Do some math so you buy right ammount and type.

Today, It is modern to use colored paint. You can google or borrow books about which colors to use, what do different colors express etc.
Some shops can mix the color for you or you can add a dye by yourself. Usually i let the shop mix it for me.

Step 3: Surface and Preparation

Unbolt, remove and cover everything you don't want to be painted. Make space in the room so you'll work faster. Clean some dust and nets with a broom or rags, clean it also from the walls (!). Use masking tape on laths, doors and window frames, radiators etc.
Make sure the tape is fully glued at least first centimeter (in the width) otherwise the paint will flow under the tape (!). Cover the floor with newspapers.

Surface:
Small craks and air bubbles should be repaired. Scrape them from both sides untill the material stops falling away. Than you fill the crack with reparatur product. Some reparaturs are already prepared and packed in tubes or you can buy it in powder. Than let it dry and use sandpaper to level the bulb with the wall. When you'r done with reparatur you should clean the dust from the floor and the wall again.
If you see big cracks, you should use plaster. If there's mold on the wall, you should use special paint and treatment. Google for it. You should also sandblast old drips and similar.

Mix and test the paint:
In the bucket you put 1/2 kg of paint and water (read instructions). Mix with the stick for about 5 min untill it has nice even flow. With the brush test the paint on the wall and dry it with hair dryer. Keep in mind that dry paint is a bit brighter than wet paint. If you'r adding a dye, you add it gradually and test more times. These tests should be always done by day with lights turned on.

When you'r satisfied with the color go ahead on next step.

Step 4: Let's Paint

First use big roller. Dive the roller in the paint, everytime for 1/2 inch only and every 1/4 turn. Than remove excess paint with slowly spinning and brushing it against the net (very important part). I usually spin it for 10 times and always into the bucket in order to have clean face. Approach the wall and start painting in up/ down direction for 4 times, than left/ right direction. Notice: same area is painted in all 4 directions. More paint you have on the roller more area you can cover so I usually paint 2 - 3 m² at the time. The paint shouldn't spray and drip from the roller.

When you finished with big roller start with small roller. The technique is the same:dive in paint, remove the paint and roll it in all 4 directions. Small roller is used for paiting corners, repairs etc.

You can pause till next day because there won't be any difference in color. Notice that every time you pause your job the paint is drying on the tool so you should clean or at least rest your tools in water.

Step 5: Finish!

Remove the tape and clean any drips with the diluent. I suggest you first test try the diluent because it can make damage on original paint.
Clean your tools with water and/ or diulent.

FINISH

Step 6: Extras

In areas around switches, coat hangers and ovens you can apply thin layer of special lacquer. Ask in the shop about it. With mentioned lecquer oil and dirt stains will be removed easier and with wet rug only. Mentioned is optional but advisable..

You can also add plaster sculptures and glue them on the wall.
For designs you can use masking tape, plastic paterns, sprays etc.

See pictures about my extras.