How many tenants/properties are feasible while working full-time?

[Lucas Mills]

I have a full-time job that I would like to continue working while getting started with real estate investing.

My short-term goal is to replace my currently monthly income of about 3k/month (after taxes) within 5 years. Based on what I'm reading, this should be feasible (but please let me know if this is not the case).

I plan to start with a "house hack" - purchase a multi-family property with an FHA loan and live on the property for x amount of time. Ideally, I will make at least $100 each month after applying the 50/50 rule. After some cursory searches on zillow last night, I almost immediately came across a property (a 4-family property) which is very close to fulfilling this goal.

My questions are as follows:

1. If I'm working an 8-5 job Thursday - Monday (Tues/Wed off), how many tenants can I realistically maintain, if any? Or must I step down from my job in order to pursue this?

2. Along with the first question, do I have to be available 24/7 in case there are issues, or is there an understanding with the tenants that issues might have to be resolved after 5pm each day or on Tues/Wed (when I'm off)? How is this best approached?

3. A bit unrelated - what (if any) are considered "emergency" issues that I absolutely must resolve ASAP or within a certain time frame? For example, I know that if my hot water goes out in my apartment, they will get someone there after hours to fix it. So do I have similar obligations with certain issues? This is one thing that is someone daunting to me (e.g., heater goes out in the middle of winter -- how does this get fixed?) I assume that you hire someone with the knowledge to come in these fix these issues, and I assume there are people that will do this at any time of the day?

In other words, what issues must I pay the most attention to and how do I resolve them (considering I have no HVAC knowledge, as it relates to my above example).