Questions about the life of WR

Does anyone have any idea of how long will the WR property of cameras and lenses last? Three years? Five years? Ten years?

I'm afraid that the WR property will deteriorate over time without our knowing and may accidentally "get it wet" and damage the equipment.

Are there anything we need to look out for to see if the seals have deteriorated? What type of conditions will accelerate the deterioration? Anything we can do to help extend the seal life?

Any guesses or specific info?
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R.I.P. -- Rejoice In Photography