I think you should test out how your skin reacts to the 10mins per day on your legs. I also feel everyones skin is different and what will cause a problem for 1 person may not for another.
I can't go in the sun due to my skin diseases (rosacea, prickle heat, sun poisoning reaction, hives) so SPF is a daily event for me LOL! Also I own clothing, hats and even my newest purchase from Amazon of a VU face visor (have no idea if it really works as I haven't taken it up to the opitical center to see if they could test it for me.
In my youth I wanted to be able to tan like my girlfriends and it was very popular to have a dark tan. With my skin type (ultra fair) that was a disaster! But I did the damage trying and well I can't go back in time and stop myself. Wish I could. I have lot's of sun damage popping up all over the place plus everything else.
I recently had a full body skin check at derm's office and thankfully nothing is cancerous. I just hope and pray that doesn't happen and take many steps to help for the last 30 yrs since I was diagnosised with rosacea. That rocked my world and sun is like putting gasoline on a raging fire.
I have family and friends that have zero issues and would never do what I do and I do not tell they should. We must go by what we each are dealing with and make the best choices with good information. I sure wish I had listened way back in the day....I was a silly teen and 20 something that didn't listen and got burned many times.
I do use a 1/4 tsp of spf on face....then 1/4 on neck....1/4 on chest or more depending on the top I have on. I have another skin condition on my neck & chest broken caps plus redness which they call Poikiloderma. Might try VBeam on this in future when I am done doing them on my face for rosacea.
Now for the rest of me...that depends...if I am wearing short sleeves I wear spf on arms/hands. Then if wearing open sandals I started doing the tops of my feet as they will tan and get strap marks. For some reason tops of my feet do tan and not burn LOL! I usually wear full pants but if it's hot out I will wear crops and then I do put spf on. So it just depends on the time of the year here (we are not like Texas) and what my plans are for the day.
Best wishes to you and hope this wasn't a novel to read