It depends upon you and your family. I grew up seeing my mom's parents about 1 weekend a month as they lived a state away and my dad's mom (grandpa deceased) about once a year for a week, she lived a 1,000 miles away.
We had an empty nest for 3 months and then the youngest grandbaby came to live with us at the ripe ole age of 6 months. That was 3 years ago. The other 5 grandchildren live about 800 miles away and we get together for a week once a year. My folks come too and we have four generations around the campfire.
It is really up to you and how much your children want you in their lives. We had to sue using grandparents rights in IN to see the youngest and we recently found out she now has a year old sister we were not told about.
Some grandparents want to be involved daily with their grandchildren other are happy with a monthly visit. Others take whatever time we can and are thankful for that.