ifixit gives a warranty on their tools and parts.
Here are some links that may help you to decide.
Excerpts from this quote from this page
"iFixit’s Lifetime Warranty ...... Batteries and other consumables are not covered by the Lifetime Warranty. Accidental damage, normal wear and tear, and labor costs are also not covered. ..... iFixit will replace any defective or malfunctioning product at no charge; if the part is no longer available, we will provide a refund."
From their warranty page
"Example: If your iPhone 5 battery replacement fails entirely after a couple months, we’ll replace it. If it loses potency after dozens and dozens of cycles, we won’t.