Your home, but only when you're speaking casually to people you're comfortable with — signals working-class identity over middle-class propriety.
Gaff is what you call your home when formality feels wrong. It's the word for where you actually live, stripped of the respectability that comes with 'house' or 'residence.' You'd say 'come round to my gaff' to friends you're comfortable with — it signals you're inviting them into your actual space, not performing hospitality.
The word traveled from Romani communities through London's working-class East End, where it originally meant the cheap theaters where poor people went for entertainment in the 1800s. Somewhere between those penny theaters closing and the 1980s, the meaning shifted — from 'place you go' to 'place you live.' That century-long gap exists because working-class speech lives in mouths, not in books.
In Ireland, especially Dublin, the word took on new life. Young people created 'free gaf' for when parents are away, 'wreak the gaf' for trashing a house. Using 'gaff' instead of 'home' announces something: you're speaking from street level, not trying to sound proper. It's linguistic class consciousness — the word itself rejects middle-class respectability.