What is the battery life of the product?

The product can be used more than 80 times on a single charge and can be charged more than 300 times. So you can expect to get plenty of use out of it before needing to recharge.

Is the lighter easy for my mom to use? She doesn't have the strength to use a traditional lighter.

Yes, simply press the safety switch at the bottom and slide up the ignition switch. She will be able to light candles faster, safer, and easier.

Is the electronic lighter childproof?

Yes, there's a safety switch so your little kids can't light it. The lighter is designed to turn off automatically if left unattended with the power on for longer than 10 seconds (the indicator light will turn off).

Does the lighter works with deeper/bigger candles?

Yes, the length of the lighter is 6.3"

Things not to do while using the lighter ?

Do not touch the arc, as there is a risk of electric shock. The lighter will make a "Zee zee" noise when lighting, which is due to high-voltage power generation, but it will not affect regular use.