Yes sunscreen or sunblock is good for your skin
You can wear sunblock or sunscreen everyday if you want too and you really should wear sunblock or sunscreen when you're out in the sun.
Too much exposure to sun can be damaging especially if you get sunburned too often as it can lead to skin cancer so you really should wear sunblock or sunscreen whenever you're gonna have your skin exposed to sun a lot.
Not wearing the sunscreen often enough can be more harmful to your skin and health than wearing sunscreen or sunblock everyday.
I always wear sunblock when the weather is hot and the sun is really beating down as it prevents skin cancer and prevents getting sunburned which is also painful.