I have come across the following two sentences from Michael Swan's practical English usage
1 I meet my mother every single day
2 I meet my friends every few days
what is the use of single in the in the sentence number 1? is it not superfluous? is not enough if we say " I meet my mother every day"
I meet my friends every five days is understandable. But what does "every few days " mean? does it mean every now and then?