I am exploring a time series with the aim of detecting obvious changes in variance over time (I have little experience in time series analysis). The hypothesis is that the series has become more stable over time (stable=decreased dispersion).
I am wondering whether there are any strategies to visually assess how a measure of dispersion (does not have to be variance) changes as the series progresses. I understand there are tests for the constant variance assumption. My outcome is a daily measure captured over 10 years, with changes between months being the relevant measure.
As a first step, I have plotted the monthly MAD (median absolute deviations) over time. However, I'm not sure that's a sensible approach.