Let $f(x,y)=0$ be (irreducible) elliptic curve over the rationals.
Is it possible:
1 Both $x,y$ to be squares infinitely often?
2 Both $x,y$ to be (arbitrary) large powers, not necessarily the same power?
For Weierstrass model, $x$ square infinitely often is possible, though I believe abc implies both can't be squares infinitely often.
For larger powers the n-conjecture implies the number of monomials can't be too small.