Here, I define the environment renumerate, which takes as a mandatory argument the repeated text. In my MWE, I invoke enumerate to show how redefinitions of \item do not extend outside of the renumerate environment. No packages necessary!
\documentclass{article}
\let\svitem\item
\newcommand\newitem{\savetext\svitem}%
\newenvironment{renumerate}[1]
{%
\def\savetext{#1}%
\renewcommand\item{\let\item\newitem\svitem}%
\begin{enumerate}%
}
{\savetext\end{enumerate}}
\begin{document}
\begin{renumerate}{My repeated text}
\item doe.
\item reh.
\item mi.
\end{renumerate}
\begin{enumerate}
\item doe.
\item reh.
\item mi.
\end{enumerate}
\end{document}

Nesting renumerate works but may not give quite what is expected:
\documentclass{article}
\let\svitem\item
\newcommand\newitem{\savetext\svitem}
\let\savetext\relax
\newenvironment{renumerate}[1]
{%
\def\savetext{#1}%
\renewcommand\item{\let\item\newitem\svitem}%
\begin{enumerate}%
}
{\savetext\end{enumerate}}
\begin{document}
\begin{renumerate}{My repeated text}
\item doe.
\item reh.
\begin{renumerate}{\textbf{Now for something different!}}
\item X.
\item Y.
\item Z.
\end{renumerate}
\item mi.
\end{renumerate}
\end{document}

1. Bla Don't do this at home, to be1. BlaDon't do this at home– user Aug 29 '17 at 13:35\newcommand{\listcontents}[1]{\item first \item second}and call each one of the my implementations asbegin{listwithdot}\listcontents\end{listwithdot}and on the other place I need the list items without a dot, I call the other list implementationbegin{listwithoutdot}\listcontents\end{listwithoutdot}– user Aug 29 '17 at 15:58