As such, consistently getting ideal performance from your circular saw requires knowing when the blade needs to be sharpened or replaced. Learning about common problems with circular saw blades can also help you better determine how to potentially guard against such problems in the future. What is the lifespan of a circular saw blade? Many factors can influence how long a circular saw's blade lasts before it starts to deliver diminishing returns. If you're new to using a circular saw, keep in mind that familiarizing yourself with circular saw beginner tips can also help you better understand how to use your saw in a way that maximizes the blade's lifespan.