How to add space between math symbols faster than existing methods

Question

I have several equations that needs extra space between math symbols. Is there any way to add space between each symbol faster than adding

\,
\:
\quad

etc, to the code?

It takes a lot of time to add the extra space for each equation in each space between symbols

I am using this code to add extra space:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[spanish]{babel}
\usepackage{multirow}
\usepackage{fancyhdr}
\usepackage{epic}
\usepackage{eepic}
\usepackage{amsmath}
\usepackage{threeparttable}
\usepackage{amscd}
\usepackage{here}
\usepackage{graphicx}
\usepackage{lscape}
\usepackage{tabularx}
\usepackage{longtable}
\usepackage{comment}
\usepackage{subfig}
\begin{document}

\begin{equation}\label{ModeloFactorizandolasK}
\dot{N_1} ={p}_{11}\,r_{1}' \,N_1 ( K_1-p_{11}N_1+p_{21}N_2 )\, + \,p_{12}\,r_2' \,N_1
( K_2\,-\,p_{12}\,N_1\,+\,p_{22}\,N_2 )
\end{equation}

\end{document}

Answer 1

I think (2) with the default TeX spacing looks best but (3) has automatically added space similar to the space added by the explicit \, in setting (1)

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[spanish]{babel}
\usepackage{multirow}
\usepackage{fancyhdr}
\usepackage{epic}
\usepackage{eepic}
\usepackage{amsmath}
\usepackage{threeparttable}
\usepackage{amscd}
\usepackage{here}
\usepackage{graphicx}
\usepackage{lscape}
\usepackage{tabularx}
\usepackage{longtable}
\usepackage{comment}
\usepackage{subfig}
\begin{document}


aaa
\begin{equation}
\dot{N_1} ={p}_{11}\,r_{1}' \,N_1 ( K_1-p_{11}N_1+p_{21}N_2 )\, + \,p_{12}\,r_2' \,N_1
( K_2\,-\,p_{12}\,N_1\,+\,p_{22}\,N_2 )
\end{equation}


bbb
\begin{equation}
\dot{N_1} ={p}_{11}r_{1}' N_1 ( K_1-p_{11}N_1+p_{21}N_2 ) + p_{12}r_2' N_1
( K_2-p_{12}N_1+p_{22}N_2 )
\end{equation}


\thinmuskip=4mu
\medmuskip=6mu plus 4mu minus 4mu
\thickmuskip=7mu plus 7mu
\scriptspace=1pt
ccc
\begin{equation}
\dot{N_1} ={p}_{11}r_{1}' N_1 ( K_1-p_{11}N_1+p_{21}N_2 ) + p_{12}r_2' N_1
( K_2-p_{12}N_1+p_{22}N_2 )
\end{equation}

\end{document}