Range anxiety is something all first-time EV owners will experience, until they get to know their car better. With an 18 mile one way commute in SoCal, I personally wouldn't worry as your Leaf will serve your needs for quite some time as long as your commute doesn't increase. And even if it does, if you can charge at work (even at 120 volts) that will help even more.
I took my brand new Leaf home 60 miles from Tustin and just barely made it home. That was in winter though and I was using the heater, and my 2012 has a more power-hungry heater than the 2013+ SV's and SL's. I also live in the foothills area so my drive home always uses more battery.
For SoCal you may want to sign up for the following charging networks: EVgo (expensive but they have the most fast charging stations in this area), ChargePoint, GreenLots (LA city and other municipalities tend to install their charging stations, particularly at curbside), and Bl!nk (once the most common, not so much now but you can still find them particularly at some IKEA locations like Burbank or West Covina). Some Metro train stations also have charging stations on the EVconnect network: https://www.metro.net/projects/ev/
You can use these to supplement home charging if you need to. Costs will vary by network and even location. For example, I "filled up" at a GreenLots curbside charging station in West LA for $2/hour. A couple of weeks ago I did so at another GreenLots station provided by SoCalEdison for a mere 70 cents/hour. OTOH fast charging (if your car is equipped with CHAdeMO) is often quite expensive; EVgo for instance charges a $4.95 connection fee on top of usage unless you are one of their monthly subscribers.
Oh and get the Plugshare app for your phone. It will show you where the charging stations are in any area and what networks they are on, including whether they are 24/7, costs (including parking costs), and sometimes detailed location information to make them easier to find. That also helps to soothe any range anxiety.