Thank You Notes - still a thing?

Yes they are still a thing! Even if they are not common in your circle sending a handwritten thank you note is a small way to thank your guests and let them know you received their gift.

For cash I usually say "Thank you for your generous gift." You could mention how it will help on your way to saving for a car, house, home improvements, etc.

OMG yes send thank you notes. For any gift, thank them for the gift, attending the wedding, and what you maybe will use it for:

Dear X,

It was so wonderful to see you at our wedding, thank you for taking the time to celebrate with us. Thank you also for the very generous $100 gift (or "the mixer", "the new towels, etc) we can't wait to use to help set up our new home (or save for a house, or treat ourselves to a nice dinner out). Hope to see you soon,

Your Name

if they didn't attend and just sent a gift, just eliminate the first part or say something like "Thank you for thinking of us on our wedding day, and thank you also for the generous gift of ____"

Yes!!! Definitely send thank you notes! People took the time to get you a present so you should take the time to write them a note. I agree with the above for cash gift thank you's.

Yes! Send them! I get so annoyed when we don't get them for showers/weddings/etc. We got a lot of cash gifts so they typically said "Thank you so much for your card & gift! Your gift went towards X Y Z".

I'm getting married this Saturday, and I definitely plan to send them

Definitely send them! For a cash gift, you don't mention the amount, just "your generous gift." And then as others have said, you indicate something about what you intend to use it for.

Yep, they're still a thing! I would say something like "thank you for your generous gift" for cash gifts