ALWAYS MIX ALL OF any powder developer. - NEVER TRY TO DIVIDE > (as there is no way of getting all ingredients properly mixed , either their weight of grain size )
I always mix the full 3.8 litre lot once , store in various sized BROWN Glass bottles filled to brim . ( I have over the years I have collected many 200ml & 250ml brown glass screw-top bottles from cough balsalms,etc )
As I always use D-76 as 1:1 dilution I find it a great developer to have in my D/room , I have used D-76 from these bottles at 12 months of age with no problems . However most years I use up this quantity within six months .
........................... Cheers Barrie B. Melbourne .
B T W -- GOOD LUCK with this forum .