Is good to not fully charge battery ? Does it extend battery life ?

Is it good to not fully charge phone or laptop battery ? Does charging of battery to less than 100% extend its lifespan ?

To increase the lifespan of lithium-ion batteries, it is recommended to not fully charge them. Lithium-ion batteries are commonly used in mobile phones or laptops. Full charge or full discharge has a negative impact on lifespan of this type of batteries.

Some manufacturers simply recommend to charge battery to less than 100%. But there are also manufacturers who recommend to charge battery only up to 80% or 90%.