Collector here since 2005 - some Hot Toys, 1/6 customs and gunpla.
Dusting your figs multiple times will inevitably mark them, besides the paint effect (faded colors and minor scratches). If the paint job was done not so right, the ink WILL be removed.
So if you want decent protection, made / buy an acrylic display. There are tons of people working if it. You still need to clean the display eventually (and acrylic got easily scratched), but not the fig.
If you want a true perfect protection and zero maintenance, put these displays inside an hermetically closed wood hack. However, you will need to made one here, spending some $ and patience.
In essence, I don't expect most people understand or even agree with all that. However some figs nowadays are extremelly hard to find. Lost it for dust is just... irrational ($ speaking). So, if this is your case, I recommend considering this setup.
