I think the rule for smart home electronics is...

You lose 50% the moment you open the box.
You lose 25% after 6 months.

At this point you are at 25% of what you paid for it. After a year you lose even more.

Example:

$6000'ish (not really sure of total because its loaded with cards) Crestron DM Switch for $300 [Link: ebay.com]

Current value is 5% of what you paid for it.