Sunday afternoon question...

After living in our rental for coming up for a year we still get other peoples mail - no problem for most of it as its from companies with return addresses on the outside. However we get the odd piece that is handwritten, looks personal and we have no forwarding address.

So should we open it to find a return address, or just pop it in the bin? The property manager is frankly crap on most things so I expect if we ever went to him, he would be useless too.