The modern Smart Phone (Like Broadband) is designed to be always on, (When was the last time you saw somebody under 50 not using his phone while doing something, (Walking, drinking, eating etc.) so yes, a good free protection will be required.

In addition, most users under 50 have a Rooted their phone, (Jailbreak on iOS) to allow them to do things the phone was not designed for, which as it bypasses a lot of security protocols makes it even more susceptible to attack.

Also, make sure you use a VPN (Virtual Private Network) App when using online banking etc. (This is of vital importance if using outside Wi-Fi) to prevent all your security details from being stolen.

If your over 50, probably less so, as you will probably be using it minimally, thus reducing any risks anyway.

Like always, be aware to be safe.

Hope this helps

Bill