[ctm92]

It's all fun until you want to sell the machine and the stickers discolored the case. Some stickers adhesive seem to react with the coating on MacBooks and permanently discolor them.

Just be aware of that :)

[jack_tripper]

If you're selling it after 10 or so years, the value of the machine has already tanked and some stickers won't impact the value any further.

[johnwalkr]

The whole MacBook lid fades from UV over time, and underneath any stickers will be darker.