There's no specific timeframe for how often you should change your crochet hooks. In fact, some people use the same hooks for decades. If the hook is in good condition, you don't have to change or replace it. But if it breaks, bends out of shape, or starts to chip around the edges, especially around the hook area, it's definitely time to get a new one. Like most crocheters, you may find that you enjoy having a variety of same size hooks which are probably different in design, material, shape, or length, and because each provides a different user experience, you like to switch them up depending on what you want to achieve at a particular time.