To wear or not to wear? That is the question when sunglasses and driving are concerned.
Generally following common sense will keep you on the right side of the law. If the sun is shining brightly you wear your shades, if it isn't you don't.
But there are times your £200 designer framed lenses or £5 service station specials can land you with a £2,500 fine and a nine penalty points.
It boils down to Rule 237 of the Highway Code which stipulates that if bright sunlight is making it difficult to see the road and other road users you must slow down or pull over.
And if you're not wearing shade to mitigate the sun's glare you could be prosecuted for driving without due care and attention, more commonly called 'careless driving'.
The offence means an on-the-spot fine of £100 and up to three penalty points on your licence - or you could go to court and face up to £2,500 in a fine and nine points.
But it is also illegal to wear some types of sunglasses while driving, reports the Plymouth Herald.
Sunglasses are divided into four categories based on how much light they filter out.
Most sunglasses will be category two - meaning they filter between 18 and 43 per cent of light and are suitable for driving.
But if you have category 4 sunglasses - which let less than eight per cent of light through - they are illegal when driving.
In the UK sunglasses must be labelled and show the filter category number and category 4 should be labelled 'not suitable for driving and road use'.
Variable tint lens sunglasses are also not suitable for driving. The tint on these glasses becomes darker when exposed to sunlight, but modern car windscreen glass filters out UV rays and means they won't work.
According to the AA: "Filter category 4 lenses only transmit between 3 per cent and 8 per cent of light and are not suitable for driving at any time."