T1i file size and printing

Hired a green new photographer to shoot an informal event I'm holding. I usually would do the photography, but because of the nature of the event I need to outsource this on a budget. Found someone who is just starting out in her photo business. For a third to a quarter of what pros charge, she'll photo the event and then provide me the entire shoot for my own purposes on dvd. I've seen her work, spoke to some of her previous clients and they say they've been happy to get away with the 1/3 price of a pro to get a decent number of shots for print.

She shoots with a T1i on its highest JPG res.(which should create about 5 MB images) She recently forwarded me a CD of an hour shoot she did with my family. It has 120 shots and the cumulative file size is 190 MB. She says she post-processes in PS. I told her too much of that and the file sizes will shrink. She's eager to learn (I know, it sounds strange for a client to be teaching the provider) and wants to know what she should do different. She says none of her clients thus far have had any problems printing up to 8 x 10 with 1.5 MB file sizes. That might be the case, but clearly this is not optimal.

So please no lectures about hiring a pro in the first place. I get it. But what might I nicely tell this young lady to do from this point forward to make sure she doesn't bork my entire event. I assume 1.5 MB sizes may run into trouble with large print sizes, no?