Should I use only original charger?

Yes. The use of low-quality chargers may, first of all, affect the warranty of device, and secondly, due to poor components under load (during charging), a very small voltage may be supplied, or it will randomly jump and give a small amperage leading to a possible malfunction in the device. 

Also, for those who like to charge phones in the car, the use of low-quality chargers can damage your device from poor voltage regulators (for example, when you press the gas pedal to the floor), or ruin the charger itself.

The same applies to USB cables, a poor-quality wire gives much less current than the original from the manufacturer, which further affects the duration of the device’s charge.