Only a few weeks ago I opened a packet (5 litre) of RA4 Agfa kit. I had this for close to three years and it worked perfectly.
On the other hand I mixed, or attempted to mix up a ½ a packet of RA4 developer that had been opened about 6 months, it was off, this was only 2 weeks ago.
You'll soon know if it's off.
Bleach I have used after 4 years.