What is an English analogous expression to "as practice shows"?

Question

In my native language there's an idiom "as practice shows" which means that your statement is based on some experience (practice).
Sometimes it's used to emphasize the difference between theoretical expectations and practical results.

For example: the manufacturer states that their device is water-proof, but as practice shows it gets broken if you use it in the rain.

I've come up with these variants, but I don't know how they sound for native English speakers:
- as practice shows
- in practice
- according to practical/live experience
- experience teaches that

Could you please tell me how would you say?

Answer 1

For example: the manufacturer states that their device is water-proof, but as practice shows it gets broken if you use it in the rain.

One such expression that would fit your sentence is "in reality":

The manufacturer states that their device is water-proof, but in reality it gets broken if you use it in the rain.

(A synonymous expression would be "in practice", as suggested in comments by @AlexT.)

I also think you are on the right track with the word "experience". Let me suggest experience shows:

The manufacturer states that their device is water-proof, but experience shows it gets broken if you use it in the rain.

You can emphasize the difference between expectation and reality even more:

Real-world experience shows this phone is not as waterproof as the vendor says it is.

(This excellent suggestion was offered by @Sven Yargs in comments.)

Answer 2

If this is purely anecdotal, the most natural way to say this, IMO, would be "the manufacturer states that their device is water-proof, but many find it gets broken if you use it in the rain." You could also say, "... but it has been shown to break if used in the rain." As you suggest, many say "Experience teaches us that..." or, perhaps more colloquial, "it's been our experience," but often the first-person pronoun is not appropriate.