‘Een in die was, een aan die bas, en een in die kas!’
– Afrikaans for ‘One to wash, one to wear, and one to spare!’
I picked up my new tennis racquet from the tennis shop today. My social club has started playing super-safe and social-distanced tennis*, and I needed one more, as a spare.
*We play on outside courts only. Each player has his/ her own set of numbered tennis balls (to handle, and to serve with). Other players pick up & pass the server’s balls to him/ her with the racquet only, so without touching them.

Higher string tension gives more control (for volleys at the net, say), but less power.
Lower string tension gives more power, but less control.