Buying a house gives you a survey of its condition and almost nothing about how to operate it. These are the things worth establishing early.
Find the shut-offs
Water main. Locate it, confirm it turns, and make sure everyone in the household knows where it is. The moment you need it is the moment there is no time to look.
Electrical panel. Find it, and check whether circuits are labelled. If not, labelling them properly is a genuinely worthwhile afternoon.
Gas shut-off, if applicable. Know where it is and what tool it needs.
Garage door manual release. The cord. Worth finding before a power outage.
Order the permit history
Worth doing early and hardly anyone does it. Request permit records for your address from the relevant jurisdiction and compare them against what physically exists.
Gaps indicate work done without a permit — a finished basement, a converted garage, a deck, an addition. Knowing about it now, with no deadline, is dramatically better than discovering it when you sell under a closing timetable.
Remember the jurisdiction question. In Seattle it is SDCI; in other cities it is that city; only unincorporated areas go through the county.
Understand what was deferred
Your inspection report noted conditions. What it could not tell you is what was deliberately postponed.
Look at the ages of the major systems. Roof, heating, water heater, electrical panel, windows. Anything approaching end of life is something you will be dealing with, and knowing which comes first lets you plan rather than react.
A water heater over eight years, a furnace over fifteen, a Western Washington roof over twenty — these are not emergencies, but they are appointments you have not made yet.
Learn your climate
Washington is two climates, and moving between them catches people out.
West of the Cascades: moss on roofs, damp crawl spaces, drainage, and moisture management generally. Gutters matter enormously. Freeze protection matters occasionally, which is why people skip it and get caught.
East of the Cascades: snow load, ice dams, sustained freeze, freeze-thaw damage to concrete and masonry, and genuine summer cooling load. Attic insulation matters more than almost anything.
If you have moved across the state, most of what you knew applies less than you think.
Go into the crawl space and attic
Both, once, early. Not because you will enjoy it, but because you need a baseline. Knowing what normal looks like in your house is what lets you recognise abnormal later.
In the crawl space: standing water, damp ground, vapour barrier condition, condensation on pipes, any smell. In the attic: insulation depth and coverage, blocked soffit vents, exhaust ducts terminating where they should not, staining on the decking.
Detectors
Test smoke and carbon monoxide detectors and check their manufacture dates. Detectors expire regardless of battery condition, and many people do not know this. A house you have just bought may have detectors installed by someone two owners ago.
Do not do everything at once
The instinct after buying is to fix everything. Resist it long enough to sequence sensibly — rough work before finish work, drainage before landscaping, panel assessment before electrification.
Living in a house through a full year teaches you things about it that no amount of planning in month one will.