These tips are really helpful. I like the soda bottle storage - cheap and informative re: fixer status.
It's what I've been doing for years. You can bleed every last bit of air out by cracking the cap open enough to squeeze the air out. This helps chems last well. Ilford recommend, from memory, using their ID-11 within six months after mixing, I once went a year (or very nearly) and it was just fine.
A few weeks ago I accidentally fixed some films with a two year old bottle of Ilford Rapid Fixer, stored as above. Picked up an old bottle by accident instead of the fresh batch. I realised half way through but the films fixed beautifully. I always do a clearing test and adjust time to suit, and never approach Ilford's recommended maximum number of films fixed per litre, so I wouldn't have expected too many problems, but it was still encouraging to see that long term storage in a 2 litre Pepsi bottle had not impacted its effectiveness to any noticeable extent.
I have read that soda bottles are not ideal because they can permit atmospheric contamination of the contents (or something like that). What I do know is I've been storing ID-11 and fixer in them for five years and haven't ever had an issue, personally. The one thing I would suggest, because the bottles are clear, is to simply store them in a dark place when not in use. Mine are either in the laundry cupboard or a 50 litre black plastic storage tub, and haven't failed me yet. I also agree with the other comments. If your films are still pink/purple, re-fix them in fresh fixer and generous rinsing. The latter will also help to remove any anti-halation dye.
Lastly, if you shoot any 35mm, hang on to the leader ends after loading your reels. I trim them down into two or three small strips and pop them into spare 35mm film containers sorted according to film type. Then, whenever I am developing a particular film, all I need to do is to grab a strip of the same film, spot it with a drop of fixer and let it work for a minute before dropping it into a small jug of fixer and timing how long it takes to clear. This will both inform the needed time for your films in the fixer, and, by noting the original clearing time of film in fresh fixer, informs you as to the effectiveness of your fix and when it is spent (Ilford suggest twice the clearing time of freshly mixed fixer as a guide for when to replace it). I believe I read the above method in one of Roger's and Frances's books originally, and it is a very easy and effective way of ensuring adequate fixing at all times.
Cheers,
Brett