I think it depends on a number of things.
Are you the type of person who just HAS to have a different outfit every evening with matching shoes?
Are you happy to use whatever suncream/showergel/shampoo you can buy in resort?
How heavy are your empty cases?
Do you like to bring back lots of fake handbags/sparkly flip-flops/pashminas?
Our cases usually weigh less than 20kgs each for 3 weeks and I take suncream and all other toiletries (although I do decant moisturiser etc so I only take what I'll use).
We also take 8 or so thick paperback books in our checked luggage as we do read a lot.
I mix & match my outfits so I wear different trousers with different tops.
IMHO, it IS do-able, even without having clothes laundered.
But, if you get it wrong - either on the outbound or inbound journey - it could be a costly mistake.
How much do TC charge for excess baggage?