I have a friend who, when asked how large an anchor always says-
" five pounds less than the heaviest you can lift off the bottom"
Bit of an exaggeration, but ---
On the other hand, a 20 pound Danforth is a monstrous big thing to stow. I just sold two of them and it's just a huge anchor- Had them left over from a 35 footer.
I use a 22 pound Bruce with 100 feet of chain (plus nylon) on my 25 footer, which has worked well over some 10,000 miles of coastal cruising. And I carry a 12 pound Hi Tensile Danforth as a backup. Plus a 15 pound Folding Northill. With separate rodes for each.
If you go traveling, take at least two, and make 'em different kinds. Then if one won't work in a particular bottom, another just might. Besides, SOMETIMES you need a Bahama Moor
