Welcome to FJ and our community.
Smithjss has a very important post for a couple reasons. First, you should monitor how your spikes wear because the style you use may impact changing time. Black Widows for example, wear faster than a Champs spike. His reply is also a reminder to not walk on concrete/asphalt because it wears the plastic faster as well.
The other subtle point is how many shoes you have in rotation. My collection is nearing 30 pairs of FJ, so I don't need to change my spikes but every couple years, if that. Hokies has over 60 pairs, so you can do that math! It's important to rotate shoes, so this will save the shoe and reduce spike wear.
Hope this helps.