I only tend to replace mine every couple months, though my hen tears through one in just a few days. They're not awfully expensive but I don't have the money to replace them as often as she destroys them! Last time I bought one of these, which is more expensive but seems to be taking her longer to tear apart.
I noticed several weeks ago after Izzy had been shredding his kabob that his poops became very watery. I thought he had ingested it and it was not agreeing with him so I took it out. I had forgotten about it and gave it to him yesterday morning. He had been fine in the morning, but early afternoon his poop was watery and he appeared to be in distress. He was holding out his wings, sitting very still, not his usual perky self. I immediately removed the kabob, and kept a very close eye on him. He did eat some seeds and millet and preened himself, but it was only in the evening that I saw a turnaround. His poops solidified and he played and chirped. This morning he is his old happy self. I put the bird kabob in the garbage!