Q:

Should I seal sandstone? Based in UK

Deciding between porcelain 18mm and sandstone 24mm both grey.
The porcelain cost about 1/3 more however if i have to seal the sandstone the cost isnt that different and over time probably works out more. But i have read conflicting literature saying it doesn't need to be sealed!
Extract from here
https://www.turnbullsonline.co.uk/inspiration/faq-i-need-seal-patio-slabs/
Do I need to seal sandstone patio slabs?
Short answer, no! Leading paving manufacturers Marshalls and Stonemarket don’t recommend coatings and sealants for their sandstone paving. Knowing this will save you time and money!
Quality Indian sandstone does not need sealing, so you won't need to seal even the cheapest Marshalls Indian Sandstone Paving.

A:

It is a personal preference to seal or not to seal. I have sand stone night stands. When we purchased I sealed incase I knock a cup of coffee over or spill something that would stain the surface I don’t want it looking bad. Yes things have spilled and they still look good. 
Another possible reason for sealing outside work is if it freezes hard. At my current location I won’t use a concrete finishing method I used in the San Francisco Bay Area , it worked great and looked cool there but the occasional hard freeze here would cause the surface to fracture, I believe the same may be true for sand stone but am not sure so if I used sand stone outside I would want to water seal it to prevent freezing damage. But as I said it is personal preference since sand stone is soft as an outside wear surface you may need to seal more often. 

