Anything that can possibly go wrong, does. Murphy's Law
If anything can go wrong fix it. Peter's Law for the Obsessive Compuslive
The whole point of these Scotch Nature posts is to enable Financial Preparation. But the only think nicer than having your cake is not having to eat it. So lets go over some quick tips and basic maintenance to prevent having to dip into that emergency fund that you've been skipping Starbucks and McDonald's to build.
When you buy expensive used things have a competent person check them out first. Fun factoid is that many automotive repair places will give a prospective used car a quick once over before you buy it for a very modest fee(sometimes just doing it for your future goodwill/business). So before you shake hands and sign a bill of sale a quick test drive past your local garage might save you from buying an obvious(to a professional) lemon. Similarly pull up KBB.com to make sure you're paying a fair price and look up some articles about what to look for during a test drive.
Get a really through home inspection on any house you purchase. Make sure you have a good idea on what those repairs would cost and factor that into any offers you make.
Regular and needed maintenance on capital items like home and vehicles is not something to cheap out on. Remember there's a difference between being cheap and being thrifty. One of those two ends up with being comfortable to well off later. That doesn't mean you don't shop around for the best prices you can get for quality work but don't put off things like transmission services or timing belts, because that will often end up with you having to look for a new care with only what the junk-yard will give you for your old one or a repair bill that will seem almost as bad.
On the Medical front one of the cheapest ways to avoid a doctor's visit and assorted costs is to get your flu shot and wash your hands regularly. You don't have to be a total germaphobe to reduce your out of pocket medical costs regularly. Alas the other thing most of us should do is even less fun and that's loose a few pounds of weight. Unfun but affording insulin is even worse.
This isn't to say that the demon Murphy won't manage to bite you anyway but when you'll have your financial preparations because you made him work for it.