I'd say we are in the middle of the road. We memorize scripture, poems and lists from First Lang. Lessons, math facts, and the occasional history or science item. However, I noticed that we were not retaining them year to year. So, I created a binder with 3 sections. I print the items we've memorized on color-coded paper (yellow for math, green for poems, etc.) and stash them between tabs.
The first "section" is a plastic page protector at the front of the binder. This is usually the new poem or verse we are memorizing. It gets practiced daily.
The next section has a set of 5 tabs (M-F). Here are some of our more important memory items like multiplication facts they struggle with, some of our more recent poems or that hard list of prepositions. I've sorted the items into one poem and one math or science memory behind each tab. Whichever day of the week it is, is the tab we recite that day.
The last section has tabs numbered 1-20 for the 20 days of school we do a month (approx). Here you will find all of the poems, chants, lists, and facts we have ever memorized sorted amongst the 20 tabs. We mark the current tab with a sticky and practice them sequentially throughout the month.
This way, the important things we are memorizing aren't slipping away from us, being pushed out by new information. Every thing gets reviewed at least once a month, some weekly and the newest are reviewed daily. It's an ever growing collection of memory work and they get satisfaction from recalling it. My two older students (8 & 9) are able to prompt each other from the book - another independent activity while I work with my youngest.
Having said that, if you have a child that struggles with memory work, I wouldn't beat them up with it. Choose only a few essential items and work on those slowly and steadily. My kids find memory work easy, so it works for us. They get it from me. If my husband had been asked to memorize all of this stuff as a child, he would have crumbled under the pressure of it. Make a judgement call based on what your children are capable of. If they aren't reaching their potential in this area, consider stepping it up, but as you know, there isn't one magic formula to education. That's why we do what we do.
Lisa