Regular readers have heard this many times, but it doesn't make it any less true.
Sometimes quality companies are discounted temporarily, and a fantastic opportunity to buy shares for the long term presents itself.
The analysts at ECP believe Xero Limited (ASX: XRO) is one such S&P/ASX 200 Index (ASX: XJO) stock at the moment.
The tech stock has fallen 5.4% over the past five weeks. It's a 14.7% tumble if you go back to the 20 July peak.
So what's doing here?
Subscription growth disappoints market
In a memo to clients, the ECP team attributed the recent losses to the New Zealand company's first half report last month.
"The result showed the core business is still growing a respectable 22% along with pleasing growth in free cash flow generation.
"Subscriber growth, however, missed expectations largely due to macro factors."
The accounting software provider and its chief executive Sukhinder Singh Cassidy are playing a delicate balancing game.
Singh Cassidy came in at the start of the year to cut costs and pivot Xero from a cash-burning growth-at-all-costs outfit to one that's more fiscally responsible.
And that means sacrificing some expansion potential.
Such a transformation will take time to complete, but the market has been impatient over the past few weeks.
"Xero is now focusing more on quality revenue growth over subscriber numbers, but despite some progress, the expected margin growth was below expectations."
This 24-bagger ASX 200 stock still has legs
However, ECP analysts are not worried about the ASX 200 business.
"Xero continues to demonstrate both its pricing power and ability to pivot to cash generation, both of which have been key pillars of our investment thesis."
A big ace up Xero's sleeve is that it has a small business client base, who find switching accounting software a drain on time and money that they do not have.
That loyalty is what is often called "stickiness" in stock markets.
Xero has made many investors wealthy since listing on the ASX in 2012 at $4.50. The shares started Thursday at $108.50, making it a 24-bagger in just 11 years.
The tech stock still commands respect among the professional community.
According to CMC Invest, 13 out of 19 analysts currently rate Xero as a buy.
