Thornflower

I am the widow of a comic book collector.  My husband loved his comics and took extremely good care of them.  Watched me like a hawk when I had one in my hands!  I estimate his little collection is between five and six thousand comics all boarded, bagged and in their special storage boxes.  They're beautiful!  I don't want to just leave them in the basement when I go--you know?--so I've decided to try to sell them.  My questions:  Is it necessary to have them graded by a professional?  Will the comic be devalued (hope that's a word) if I don't?  Will a picture serve as well as a grade?  I'll have to rip tape off a lot of bags to do it myself and $50 per book . . .  well.  I have been learning about grading.  The earliest comic I saw was a Batman, 1983, in near mint condition.  Staples are in place, magazine is flat, still glossy, nothing missing and only a tiny fold on the right bottom edge with no loss of color.  I think I understand, but is that good enough?  Is the investment of this much work, time and studying worth the return I could get considering the age of the comics?  One last question:  I feel I should have a list of everything in those boxes, which I have been compiling.  My local comic consignment shop says that's unnecessary, they'll do it for me if I hire them.  But I'd still need my own list even if I hired them, wouldn't I?  Please help me.  I need advice and direction.