My one year old iMac needed a boost in memory (as do I-but that's another story). I used the Chat window, 'chatted' with a knowledgeable tech, asked a few questions and then ordered my memory chips.
They arrived two days later and thanks to OWC videos, my new RAM was installed, EASILY, in under 3 minutes!
I've purchased several products from OWC over the years and they just always come through with great deals, great videos and great technical assistance if you need it. Thanks, OWC!!!! 5 stars, as usual! :-)