No, you only need to purchase in-app premium features once and they are enabled on all your devices, as long as they’re on the same platform and app store.
When you purchase any of the in-app premium features in Squid, they are tied to your app store account (e.g. Google account for Google Play, Samsung account for Samsung GALAXY Apps, Microsoft account for Windows Apps) and managed by the app store you purchased them from. When you reinstall Squid on the same device, or install Squid on another device, you just need to make sure you download Squid from the same app store (e.g. Google Play, Samsung GALAXY Apps) and that you're signed into the same account that you made the in-app purchases with.
For example, if you download Squid from Google Play and buy the Tool Pack, then purchase a new device or factory reset your existing device, you just need to make sure you're signed into the same Google account and download Squid from Google Play again and your Tool Pack purchase will be enabled automatically.
Please note that purchases made in Squid for Android must be re-purchased in Squid for Windows (and vice versa) since purchases are not transferable between platforms.
For information on switching app stores and platforms, see What happened to my premium feature purchases?