I use SPF 50 on the kids and myself. My husband uses a lower SPF but he is not as fair-skinned as we are. As a kid I used a German sunscreen that was SPF 75. I have never seen an SPF 75 in the U.S. 

I had one very bad burn on my back as an 8-year-old and another serious burn on my back as an adult. Both times it was due to not applying sunscreen. I am a fanatic about sunscreen. 

I have used different brands over the years. Here's my take on sunscreen/sun exposure:

• I never used sunscreen on a baby less than 6 months. I limited sun exposure until the baby was over 6 months of age.
• Coppertone Baby is excellent for babies up to late elementary school age. Comes in the pink bottle. It is a thick liquid.
• For active kids, Banana Boat or Coppertone Active is excellent. It is thick, plus resistant to sweat. I reapply after swimming for a long period.
• When my kids were about 8, I started letting them sunscreen their arms and legs. I would do their backs and chest.
• With my tween and teen, I trust them to apply sunscreen.
• Each of the kids carries a sunscreen in their pool bag in case they go to the pool with a friend.
• The kids wore rashguard shirts on the beach and at the pool until around age 10.
• If you need sunscreen due to fair skin AND you are going to the beach, apply sunscreen before you go on the beach. Applying sunscreen to already sandy legs can result in uneven sunscreen coverage.
• Avoid spray sunscreens! The spray will not cover all areas. I find myself applying twice as much spray to be sure.
• Only use cream sunscreens. I like to see the cream on the children's skin to know that I have covered each body part.
• We have a house rule that if a child refuses to use sunscreen the child does not go outside. No exceptions.
• The worst time of year for sunburn is April/May and September/October. At these times of the year, the sun can be bright but I don't think about using sunscreen. Invariably one of the kid ends up with racoon eyes.