I'm not sure if it's more or less often now, but over decades almost everything breaks one way or another.
Even if your code, OS and hardware had no bugs and was designed perfectly and you keep the same hardware to run you code forever - there's layers under the hardware - the reality outside the computer.
You have written perfectly secure website. Then quantum computers happen.
Countries are created and fall apart. People switch writing systems and currencies. Calendars get updated.
Your code might technically work after 100 years, but with almost 100% probability it won't be useful for anything.
Even if your code, OS and hardware had no bugs and was designed perfectly and you keep the same hardware to run you code forever - there's layers under the hardware - the reality outside the computer.
You have written perfectly secure website. Then quantum computers happen.
Countries are created and fall apart. People switch writing systems and currencies. Calendars get updated.
Your code might technically work after 100 years, but with almost 100% probability it won't be useful for anything.