First of all a quick guide to sunscreens:
There are two types of harmful sun rays: UVA-aging rays, and UVB-burning rays. . While UVA rays don't cause sunburn, they penetrate deeply into skin and cause wrinkles. 90% of skin changes associated with aging are really caused by a lifetime's exposure to UVA rays. Clearly, you'll want a sunscreen with broad-spectrum or multi-spectrum protection for both UVB and UVA. The SPF factor rates how effective the sunscreen is in preventing sunburn caused by UVB rays only. If you'd normally burn in 10 minutes, SPF 15 multiplies that by a factor of 15, meaning you could go 150 minutes before burning.
For the vast majority of people, SPF 15 is fine. But people who have very fair skin, a family history of skin cancer, or conditions like lupus that increase sensitivity to sunlight should consider SPF 30 or higher.
Keep in mind that the higher the SPF, the smaller the increased benefit: contrary to what you might think, SPF 30 isn't twice as strong as SPF 15. While SPF 15 filters out 93% of UVB, SPF 30 filters out 97%, only a slight improvement. There are advises against using spray sunscreens since they often don’t offer even protection and pose inhalation risks, as well as SPF values higher than 50+ because they offer users a false sense of security.
There are two major types of sunscreens: chemical and mineral.
So this is my conclusion: