Greetings @KeriRaeBoyle 
That’s a great question, and one that will likely depend on the type of spell and the materials used! Usually, for materials used in general spellwork, I’d say absolutely go ahead and reuse them! 
Like Siofra said, it’s a good idea to cleanse tools to refresh them in between spellwork. This can not only purify any lingering energies and prevent intention leakage between spells, it can also help to recharge and energize your tools to further enhance your spellwork. Think charging tools under moonlight- this is both cleansing and charging for your magickal tools 
As for organic materials, well- it depends. In herbalism and kitchen witchery, you wouldn’t want to reuse raw materials that had been soaking in a concoction for months. The liquid would have absorbed all beneficial properties- the used leaves/plants/fruits/etc themselves have been completely drained. They wouldn’t have any worth in another blend, and would be quite frankly disgusting in any food! 
Additionally, I would strongly advise against re-using any materials that were used in Baneful Magick 
Every witch will decide for themselves when it is okay to reuse things and when it is better to respectfully dispose of things- rather than try to reuse drained materials. On that note, for disposal ideas, I recommend visiting the spell disposal discussions:
→ How to dispose of spell remains
→ Disposal of spell remains
→ Water disposal after spell or ritual
My best advice for you would be to take a look at your tools and materials- what is easy to replace? What things are difficult or irreplaceable? You can also experiment with recycling materials and see how that manifests in your spellwork
I’m sure you will find what works best for you, Keri! Good luck and blessed be! 
Me too! 
