Are you a bit sentimental when it comes to throwing certain things away? Items that were given to you by a special person, things you collected on a memorable holiday, your children's art work/toys/clothes - in fact anything to do with your children!
I am not a sentimental person when it comes to most belongings and sometimes take it too far on the de-cluttering side of things, occasionally having wished there were things I'd kept instead of throwing away.
I think there is a happy medium between being a hoarder because you just don't know how to decide what to keep and being a minimalist that likes to get rid of everything!
I think also with having children it can be really hard as you don't want to throw things away that they've made or given to you, but you can't possibly keep it all - my daughter could have filled a large box every week when she first started school with all of her art work and creative creations!!
So I decided that memory boxes were the way to go. Each of the children has one and my husband and I share one. We keep the boxes on the top shelf of our wardrobe and anytime there is something in particular that we think we'd like to keep then we pop it in our boxes.
We try to think carefully about items every time they might go into the boxes and generally things from special occasions such as birthdays, Christmas, Mother's/Father's Day, school awards/certificates and medals etc all get put in. All other art work from school or special things the children have made we display on a small board in the playroom for a while and once we have more to fill the board then we take it down and recycle anything made of paper/cardboard etc.
Once the boxes are full we take them down from the shelf, empty them out and organise them a bit better before putting the boxes up into the loft. I sort out the items in the boxes into large envelopes (special cards in one, art work in another etc) or plastic air tight containers if there is anything that could deteriorate over long periods of time.
Once re-organised I sometimes find I have actually created a bit more space in the box and therefore continue to use it for a bit longer. But once actually full, they go up into the loft with a label on the box saying who it belongs to and the dates between which the box was filled.
I found that for my children's first year after being born I filled one box and after that it took nearly 2 years to fill a box as I was quite ruthless about not putting anything and everything in them. You just need to think about what your children will actually appreciate you keeping to look at as adults and although lots of their old art work is nice, they'd be just as happy seeing a few select really lovely pieces.