Being away and landlord

My tenants in San Francisco condominium are two engineers. 

Since I intended to travel and stay away from the condo, I clarified them my priority was to find independent renters. For example, I expect the tenant to know how to reset a disposer or look it up at YouTube before asking someone to fix it.
They were like 😉 "We will be fine!!"😉
And yet, they have some issue almost every month to email me.
Once they emailed me to ask which light bulb to buy for replacement on a light fixture, how to replace, and if that cost of bulbs can be deducted from their rent.
"Aren't you guys engineers? Can you look closely and figure the ef out?" - I didn't say that out loud, and I wrote back that I left some extra bulbs in a closet; the bulbs have sensitive tiny pins that easily bend; they need to be inserted straight; purchasing new light bulbs should be expense of tenants.
 To my such response, they didn't reply. Yet they sent me another problem next month. 
I could have hired a property management company or person for 5%~10% of the rent amount.
Then two friends of mine offered me free help, so I didn't hire anyone before my departure.
Though these two friend are pretty much unavailable to help when I need a hand on site. 
 However long this current status can continue, or how long for me to rent the place out and to remain a landlord, I probably have some challenges. 
I do like fixing thing around home. And yes it would be more fun to spend time around home with friends than just wandering new places ranbomly.
Well, tomorrow I am gonna meet some elephants. I should go to bed.
Oyasumi nasai😙