I lube my X pedals about once a week. If I don't, the cleat on the foot I clip in and out of gets a little difficult to deal with.
I just read the FAQ page to DH, Catrin. Usually, you don't lube mountain bike pedals like Frogs, which is why we never have lubed them. I haven't had any difficulty getting into the Frogs, since my initial adaptation to them. I'm actually afraid lubing them would make me unclip in an unwanted situation, as I really had to practice for this not to happen! But, if it's recommended, I will start doing this.
2015 Trek Silque SSL
Specialized Oura
2011 Guru Praemio
Specialized Oura
2017 Specialized Ariel Sport