I am 3 weeks into my first plan which is the 18 week sweet spot plan. I initially started the plan just using my HR monitor but soon realised it was going to be better with a power meter. So I bought a power meter and used it last weekend for a fondo that I had signed up to do prior to starting the plan. The fondo was full gas for a lot of it and I took my 20 minute peak power as my FTP to start training with the power meter rather than try and fit an FTP test into week 3 of the plan. Next week is recovery week so I am wondering if I should redo my field test at the end of next week to get a more accurate FTP number. Appreciate if you could tell me if this is necessary/ a good idea?