I always keep the ones from my family, sons, daughters in law and grandchildren. I have Birthday, Valentine and Christmas cards to and from my then boyfriend in the 60's (who became my husband). They are precious to me and many is the time I get them all out and read through them and they brings tears to my eyes as they were the start of a nearly 60 year old relationship. I kept all our grandchildrens drawings they made for me. I am sentimental and have all the decorations from our wedding cake, place settings and invitations and telegrams, even the glass tumbler I was given at school when Queen Elizabeth the 2nd was crowned. God help our family when they start to look through the big ottoman memory box, I know they will find it very interesting as I wrote a diary about our lives in the 40's onwards and how I met their dad etc. etc.
I wish my mum and dad had done the same, I would have loved to have been able to read all their cards they sent each other and seen their wedding invitations etc. they are a part of our history.