Maintenance.
A mechanical mod requires regular maintenance, especially on the connectors (top cap and switch).
The dismantling of these parts is easy, once disassembled clean the whole with acetone, you can apply graphite, it will bring more softness to the switch and will space out the cleanings.
see the graphite application video
Any product is to be prohibited and will void the warranty.
Brass gets a patina, regular maintenance with a cotton cloth will sublimate your mod while letting it get a patina.
Carbon, ceramic and titanium do not require any maintenance: a simple damp cloth will suffice.
The maintenance of the princeps requires high quality leather grease of artisanal and natural manufacture.
A 15 € jar of grease will last for years, so saving on this product is not wise.
AVOID RIDING LEATHER PRODUCTS, they are not suitable and may damage your leather.
Lubrication once a month at the most is recommended, paying particular attention to the seams.
If, visually, the leather does not need greasing, postpone the maintenance.
Use leather goods products.