I'm based of Southern California in an area that has relatively small lots. When we moved in the developer of my home planted ficus trees around the side and back for privacy (he also built the home next-door and did the same thing), the exact type of which I'm not certain of. My neighbors have let theirs get way out of hand and are over 30 feet tall while being only approximately 5 feet, separated by concrete walkway walk, from the footprint of the foundation. There's were planted in 2016 and mine in 2018. I know ficus have a reputation for creating issues with regard to the size of their root system and I'm concerned about my foundation (there are no visible roots anywhere above ground). I'm looking for feedback on this. What is the recommended max height they should be in context? What variables, such as trunk diameter, should be taken into account to assess risk? For those variables, in the context of the situation, what is the max recommended? Thanks in advance for any feedback.