Everyone has an opinion on this one, and most of the opinions were formed before doing any arithmetic. I'm not going to tell you which side wins, because it genuinely depends on your situation. What I can do is show you where the usual comparison goes wrong, and what the honest version looks like.
The comparison everyone makes, and why it's wrong
The standard move is to put your rent next to a mortgage payment. Say you're looking at a $400,000 home with 20% down. That leaves a $320,000 loan, which at 6.5% over 30 years costs $2,022.62 a month in principal and interest. If your rent is higher than that, buying looks obvious. If it's lower, renting looks obvious.
Both conclusions are wrong, because that $2,022.62 isn't what owning costs. It's just the loan. Rent, on the other hand, really is the whole cost of renting your home. You're comparing a complete number against a partial one, and the partial one always flatters buying.
What owning actually costs
Start with the payment, then keep adding. Property tax comes every year whether you like it or not. Homeowner's insurance sits on top. Then there's maintenance, which is the sneaky one: boilers fail, roofs age, gutters clog, and none of it is optional. As a renter those bills belong to your landlord. As an owner they're all yours, and they arrive on their own schedule, not yours.
Then there are transaction costs, which people consistently forget because they don't show up monthly. Buying a home costs several percent of the price in fees, and selling costs several percent again. On a $400,000 home, each percent is $4,000, so "several percent in and several percent out" is serious money. You pay it whether the move goes well or badly.
One more cost that never appears on any statement: the deposit itself. That 20% down on our example is $80,000 of cash that's now locked in the walls of a house. If it weren't, it could be invested and earning a return. Economists call that opportunity cost. I'd just call it the return you gave up, and it belongs in the comparison even though nobody sends you a bill for it.
What renting actually buys
Renting isn't throwing money away. It's paying for housing plus flexibility. You can leave at the end of a lease. You can chase a job in another city, upsize, downsize, or escape a bad neighbourhood, all without paying several percent of a house price for the privilege. When the boiler dies, you send a message instead of a payment.
Owning buys the opposite bundle: stability and forced saving. Nobody can decline to renew your lease on your own house. Your principal payments build equity whether you feel disciplined that month or not, and for a lot of people that forced saving is the only saving that reliably happens. I don't think that's irrational at all. It's just worth naming what you're paying for, on both sides.
The variable that decides it: how long you stay
Here's the honest answer, and it's unsatisfying: it depends, and mostly on time. Those transaction costs on the way in and out are fixed. Stay two years and they're spread across 24 months, which is brutal. Stay fifteen years and the same costs fade into insignificance, while your equity quietly builds.
That's why short stays usually favour renting. It's not that renting is cheaper in some cosmic sense. It's that buying has a large entry and exit fee, and short stays don't give it time to amortise. If there's a decent chance you'll move within a few years, for work, family, or plain restlessness, renting probably wins even when the monthly numbers say otherwise.
If you're settled, plan to stay put for a long stretch, and can genuinely afford the full cost of owning rather than just the mortgage payment, buying starts to earn its keep.
Run your own numbers
The way to make this real is to price both sides properly for your actual situation. Start with the rent affordability calculator to see what renting sensibly costs at your income. Then build the ownership side: the mortgage calculator gives you the principal and interest, and you add tax, insurance and a maintenance allowance on top. Finally, sanity-check the whole thing against your income with the home affordability calculator.
If buying still wins after you've counted everything, buy with confidence. If it doesn't, rent without guilt. The only losing move is doing the comparison with half the costs missing, which is exactly how most people do it.