This is the question I'd be embarrassed to ask out loud. Everyone talks about the two year rule like it's obvious you'll make it, but what if I get 18 months in and I genuinely cannot live in the dust anymore. Do I lose the whole exclusion or just part of it? Someone told me there's a partial version if you move for a job, which sounds like the kind of thing people say confidently and get wrong.
Answer
Selling before you hit two years of ownership and use generally means you don't qualify for the full exclusion, and your gain gets taxed. Held under a year, the gain is short term and taxed at ordinary income rates. Held over a year but under two, it's long-term capital gain, taxed at long-term rates, which are usually lower. So 18 months is better than 11 months, and both are worse than 24 months.
The partial version your friend mentioned is real in outline. The tax code allows a reduced exclusion in certain circumstances, including some job changes, some health reasons, and some unforeseeable events, and the reduced amount is prorated based on how long you actually lived there. Whether your specific reason qualifies is genuinely a question for a tax professional, because the categories have definitions and "I hated the dust" isn't one of them.
Here's the part worth planning for now. The reason people bail at 18 months is almost never the tax math. It's that they gutted three rooms at once and had nowhere to eat, sleep, or wash for months. If you sequence the work so one bathroom and some version of a kitchen stay usable at all times, the two years get a lot more survivable. Do the ugly, disruptive, whole-house items first while you still have energy, and save cosmetic work for the last stretch when you're tired of it. That sequencing decision does more to protect your tax treatment than anything you'll read about the rule itself.