A slow website leads to a lower conversion rate. You should regularly run website speed tests to ensure your site is not loading slow for your customers. You can do that by going gtmetrix.com, tools.pingdom.com, or pagespeed.web.dev and running a speed report on your website.
You should also check the different pathways a customer might take on your website to ensure they have the best experience possible. You want to remove as many hurdles as possible that might frustrate the user.