Power consumption
The total power consumed by the electric planer during operation. The more powerful the tool, the generally higher its productivity and the better it is suitable for large volumes of work and/or hardwoods. Here, however, it must be taken into account that the effective power (the power supplied by the unit directly to the working tool) is anyway lower than the consumed one, but it is far from always indicated. Therefore, it is quite possible to compare different models with each other precisely in terms of power consumption.
Note that more power means higher electricity consumption, and also, most often, more weight and cost of the tool. Therefore, it does not always make sense to chase the most powerful units. So, for occasional use and small volumes of work, a power of 500-600 W is considered quite sufficient; for regular work on relatively soft wood, 700-800 W is enough, and professional models have a power of more than 1000 W.
Planing depth
The greatest thickness of the layer of material that the planer can remove in one pass (most often the design provides for depth adjustment). The larger this parameter, the more performant the tool will be and the better it will be suitable for large-scale work. On the other hand, in fact it is rarely necessary to remove a large amount of material at a time, and tools capable of this require powerful (and therefore expensive) motors. Therefore, in most consumer-level models, the planing depth does not exceed 2 mm; more "deeper" units, usually, belong to the professional class.
