Normally a 2-sided error randomized algorithm will have some constant error $\varepsilon < 1/2$. We know that we can replace the error term for any inverse polynomial. And the inverse polynomial can be replace for an inverse exponential.We know that we can replace the error term for any inverse polynomial. And the inverse polynomial can be replaced for an inverse exponential. Say that we have an algorithm $A$ with $\varepsilon_A=1/p(n)$ for some polynomial $p$ that runs in $T(n)$ steps, and by repeating the algorithm $O(\log \frac{1}{\varepsilon})$ times we obtain and algorithm $B$ with success probability close to 1 but with a logarithmic overhead.
My question is:
(1) If the error decreases polynomially faster, for practical purposes, do we still need to repeat the algorithm several times? Because if we do so we get a logarithmic term (which is not desired), but leaving it as it is, the algorithm will still have a success probability close to 1 for sufficiently large $n$.
(2) What about an exponentially faster decreasing error? Here it seems that we don't need to repeat the algorithm at all.
The same questions apply for 1-sided and 0-sided errors.