It's no secret that reeds are expensive. Tenor and bari players can attest that larger reeds are more expensive than small reeds, and unfortunately, larger reeds are also more likely to warp.
There are two kinds of warping:
1. The tip of the reed dries out and becomes wavy. This is a pretty simple fix, since soaking the reed will flatten it out again.
2. The heel of the reed (the flat side which has writing on it) bulges outward and the reed cannot seal properly to the mouthpiece.
Warping is caused by humidity and sudden changes in weather, and since playing creates a humid environment, big reeds only last so long before the cane starts to change. However, reeds last longer when they are in environment with controlled humidity.
Two things to help:
1. Alternate reeds. I have one box open at a time and alternate between each one. I'll play each reed for a few minutes the first time I open the box, and once I've "seasoned" them by playing each reed for a little longer each day, I can then play them for a maximum of one hour each.
2. Use a humidifier. Rico makes Reed Vitalizer packs with various humidities and last several months. These are most effective if you keep reeds in a closed environment like a plastic bag or Ziploc airtight container.
3. Recycle. One final way to save money is to save reeds and use them when the season changes. Reeds that sound bad in high humidity may sound great on days/months where the humidity is relatively low.