OK - I spend a lot of time on the summits… and the beloved EFHWs (40/20/15/10m) are a bit older… but I was still surprised at how much the wires have stretched.
When I’m out and about with the KX2, pressing the ATU button is standard… no matter which antenna I use. I have my own resonant antennas for the QRP devices (Venus, QCX Mini, etc.).
As part of the 10m challenge, I sometimes take a small PA with me… and recently I had a SWR meter with me again. The SWR values amazed me. Somehow I remembered them better.
Today I checked my two EFHW (0.14mm² and 0.22 mm² - wire from SOTABEAMS) with the NANO VNA and saw how out of alignment the curves were. I shortened the thin wire by about 15 cm and the thicker wire by about 7 cm. I will cut new wires soon.
Maybe I should attach the NANO VNA every now and then… especially when I have to pull a little harder to get the wire out of the tree. 
73 Armin