I bought the old Geocaching.com app a while back for $10 to get full features. Fast forward, I hadn't gone caching in quite a while, and decided it was time so I pulled up the app. Behold, the app is dead and you need to download a new one. OK, I do that, only to find out that you need to pay $30 per year to get the full features on the new app...even though I had paid for the old app!! I am really not happy about that. You can access many caches for "free" but the more difficult ones you need to pay for. Supposedly you can still see them all on the website but it is more of a pain to hunt and log w/o the app functionality. I guess when I find all the free caches in my area maybe I'll buy the membership for a year and look for the other ones. It sucks because the app really is a nice way to hunt. When I first geocached some 15 years ago, I had to log on at home, print out sheets for the caches I wanted to do, plug them into my GPS, go hunting, come home, get on the PC and log the visits... Now you can do it all in moments from your phone!
You've been caching a little longer than me. I started in 2009. Like you, I started with a free membership, looking at caches on a map, printing the co-ordinates and other info onto paper, then out 'in the field' having to enter the co-ordinates into my GPS receiver. It's all changed since then!
I'm now a geocaching.com 'premium' member, which does mean I pay each year (£25). Just to clarify a few things - you don't pay for "
more difficult ones". There are indeed geocache hides that are for premium members only, but they tend to be no easier or harder than 'standard' ones. The reason some are made 'premium' only is to try and stop those who spoil the game by signing up with a free account then stealing/vandalising/spoiling some caches that are perhaps more elaborate, that have taken a long time to make/place and/or cost a fair bit in materials.
I use something called c:geo (Android only) on my phone (there's a free one for Apple too). c:geo is free, and is fully functional for non-premium and premium members alike. It is a brilliant app, especially as it's free! However, having a premium membership means that c:geo can 'access more info' and perform in 'better ways' (here's not the place to discuss that though!).
What I can say is if you're into you're torches (or flashlights!) then you'll probably really enjoy 'night caching'. Night caching is simply geocaching but intended to be carried out in the dark. Often the caches will involve reflective material that blends in during daylight but when picked out with a torch at night light up like a beacon - all good fun! I've found the brighter the torch and the greater the throw the better, floody stuff isn't quite as useful for picking up reflective material at great distances. I'll usually use two torches, a floody one to see where I'm going and a long throw to pick out the markers.