Like some people of a certain age my sister-in-law is a bit of a tea snob. It's usually Darjeeling made in a tea pot (sometimes even with a crochetted tea cosy (ffs)) and served in bone china. Of course it has to brew for about half an hour. It's usually quite nice when it arrives but I'm not sure it's worth the faffing and waiting. On the other hand, I've spend a lot of time in a care home over the last few years and made thousands of cups of tea for people who aren't particualrly choosy - chuck a cheap tea bag in a mug add water and milk and Bob's your uncle everybody's happy. Now, I do like tea but I can't remember ever making tea in a cave and that's because I've always gone for instant coffee or hot chocolate. You can get instant tea and although I've never tried it, it just might be OK and may be worth trying if your the sort of person who insists on tea. But I would say definitely in a cave go for hot drinks that are easy to make. Certainly don't go for the bone china and large-leaf darjeeling and even avoid tea bags or any other sort of fiddly tea.