I have been using Ilford lc29 one shot. When ever I mix up a batch, I always ensure that I refill the concentrate bottle with some glass beads to bring the level up and tightly recap. According to the spec sheets, lc29 should keep for 36 months in unopened bottles and 6 months in half full opened bottles.
Considering that I am pushing the air out and considering that the bottle isn't perfectly factory sealed, what would be a fair lifespan for a bottle such as this? Is there an easy way to test the developer?
I am thinking of trying DD-x next. what considerations would I need for long storage life of this developer (considering that I shoot on average 2 rolls a month)