If they are NGK iridium plugs and you know they are still within their recommended service life I would leave them alone. Assuming they are the correct specification for the car they would have been accurately gapped when new and erode very slowly compared to older type plug and ignition coil technology. The iridium tip is very brittle and easily damaged when measuring or attempting to alter the gap.
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Even removing plugs just to check them visually comes with a downside. The compression sealing washers used on many types of plug are meant to be 'once only' seals' .When new they compress for a good seal. If the plug is inserted a second time the seal is already flattened , which can affect the quality of the seal, and torque settings.
Ideally you should fit new washers if reusing , but many dont bother. And replacement washers may not be readily available these days.