life shelf of powder chemical

is someone know what is the life shelf of the chemical powder for developing?
I keep the powder in the warehouse, without windows and usually warm temperatures
i use it before but i want to know if the powder has a time life shelf to know if i can continue to use it.
i purchased it in about 3 years.

I'm sure there are exception but commercially available powders, in sealed packages, can normally last indefinitely. They typically only react/degrade when exposed to air or water.

I keep mine in PET plastic bottles (which are everywhere) and, for years and years, no problems. In fact, I still have some Metol from the 1970s that remains fine (even though PET plastic was not around then. - David Lyga

It is best to leave photochemicals, such as developers and fixers in their original containers. Store them where they will not be exposed to extremes in temperature. Handle bagged products gently to avoid any punctures. If possible do not buy anymore than can be used in a reasonable length of time.

As a rule of thumb, indefinitely. Chemicals packed in sealed cans are certainly good for 50 years or more, as long as the can hasn't rusted through or been punctured. Chemicals now mostly come in sealed soft packs. They are potentially just as good, but they are more subject to damage. As long as the material remains a free flowing powder and not hard chunks, it is probably OK (a little crusting is OK, just not big hard chunks).