People who use XTOL with no problems should speak up. I have used 1 litre packages of XTOL for 3 years. The dilution ratios I use to develop Verichrome, Tri-X and FP-4 is 1:2 in medium format and 1:1 in small format. I experienced one bad roll out of about 100 and it was APX 100. I normally reduce the recommended development times by about 10% as I use a condensor enlarger. To be safe I mix the stock developer in distilled water and will toss any remaining developer out after about 4 months. A recent article in Photo Techniques found XTOL keeps longer than any developer, including D-76.(posted 8400 days ago)