There has been a debate in design circles for years about whether spec work is productive or destructive to the designer. Arguments can be made for both sides and sites exist that support both views and profit from them.
As for my personal opinion, I only support it if it falls under the category of personal work, meant to show your skills or stretch your creative muscle.
It seems the crew at Topic Simple shares the same view and has created a video to support it. It’s short and sweet, giving intelligent definitions and arguments to support their belief. Check it out below and hit their website here to view more of their videos.