ID-11 storage?

Hi,

Really simple question. Got into my darkroom stuff a few years ago, and now have come back to it. Someone recommended that I use ID-11 as a film developer (powder, which I wasn't used to). Can't find any info online/on packaging about storage. Shoved my stock into a clear plastic container, then it occurred to me that it might have been photosenstive and I therefore may have screwed it up. Don't want to risk developing another film with it if it's no good!
Can anyone help? Sorry for simplicity of question.

Cheers!

Clear is OK, keep it out of direct sunlight, keep it cool. Full and airtight is the most important thing for keeping it.
Ilford say six months full and one month half full.

Try next time to mix that powder to make a working solution before you develop enough numbers of film, so then you can use all or most of the developer within time less than 1 year, so you don't waste it, ID-11 coming for 1L, if i dilute for 1+4 one shot then i can develop 4 films before it is finished, so i will plan to have at least 5 films before i use ID-11.

I use brown storage containers so it might save the developer a bit longer and for sure i keep that container in safe dark cold/normal temp place, in all cases what is the point to buy a developer and don't keep/store it safe and i don't use it in less than 1 year or say 1 year for those quick exhaust developers?!!!