Most scent advice is written as though a fragrance works the same everywhere. It does not. The same candle that is perfect on a bedside table will be almost undetectable in an open-plan living room, and overwhelming in a small bathroom.
Three things decide it: how big the room is, how much air moves through it, and what you do in there.
Bedroom — soft, low, and not too sweet
A bedroom is small, still, and you are in it for hours without leaving. That means a fragrance builds rather than disperses. Choose something you would be happy to smell continuously.
Lavender, sandalwood, soft rose and light musks work. Avoid anything sharply sweet or foody — it is pleasant for ten minutes and cloying by the end of an evening.
A single-wick candle is enough. In a bedroom, a three-wick is usually too much.
Living room — the one place to go bigger
Living rooms are large, people move through them, and doors open. Fragrance disperses fast. This is where a multi-wick vessel earns its price: three flames melt the whole surface, and a full melt pool is what actually throws scent.
Woods, resins, fig, cedar and amber hold up in a big space without becoming sickly.
Kitchen — fight cooking, do not blend with it
The mistake is a vanilla or dessert scent in a kitchen. It mixes with whatever is on the stove and both smell worse.
Citrus, mint, basil and sea salt cut through cooking smells instead of layering onto them. Light it after cooking rather than during.
Bathroom — small, humid, needs less than you think
Bathrooms are tiny and hold humidity, which carries fragrance further. A candle that seems mild in a shop will be strong here.
Choose a small votive over a large vessel, and lean clean: eucalyptus, sea salt, white florals.
Entrance — the one people remember
The hallway is the first thing a guest smells and it sets the impression of the whole house. It is also usually draughty, so scent vanishes quickly.
Something warm and definite — amber, oud, marigold — placed on a console table away from the door itself.
A note on strength
If you are unsure, buy smaller. A scent that is slightly too faint is a mild disappointment. One that is too strong makes a room unusable, and you will not burn it again.