It's whatever makes sense for your financial status and lifestyle.

It’s meant as a deterrent so the tenant is more conscious of the energy they use.

These phrases conjure visions of an ideal lifestyle, but the reality is far more nuanced.

What investment will get you a greater return and fit with other aspects of your lifestyle and investment goals? 

No fixed amount of money will enable you to maintain your current lifestyle over time.For example, suppose you buy a property where rents increase by 2% per year and inflation is 5%.

As copied and pasted from above-(1) more than one-half of the personal services the taxpayer performs in trades or businesses during the tax year are in real property trades or businesses in which the taxpayer materially participatesThat's how I understand the W-2 problem... it is hard to say you spend more time on real estate than any other activity if you work 2,080 hours.Another consideration is how much you rely on the W-2 income for lifestyle versus rental income.

It's essential to consider and appreciate the diversity of housing options available, each serving different needs and lifestyles.

Make sure the math checks out and your lifestyle energy works with the math.  

not everyone can given family / lifestyle. 

Keep in mind your goals, time, energy, and the lifestyle you want to have or are willing to have.