I believe that debt if addressed intelligently is an excellent strategy to consider. Here are some of the following examples where I believe debt is appropriate.
Take the net income (gross income less all expenses) earnt from the investment. Divide the income by the interest you will be paying. For example if a property is worth $500,000 and is rented for $26,000. Holding costs are calculated to be $4,000pa (rates, insurance, management fees, strata etc). If the loan interest is 5% then divide this by $22,000 ($26,000 gross rent less $4,000 expenses). The loan amount therefore for this property investment to be neutrally geared is $440,000. For this investor to have no additional ongoing out of pocket expenses $60,000 deposit is required (plus purchase costs & stamp duty). Note the investor should also be mindful of the opportunity costs (lost/gained) of their deposit & fees as they are now tied up within the one investment.
Considering a career/business future may be another 20-30 years. If your income increases by $15,000 per year from a more specialist role, or you can qualify for a higher pay grade, then over the space of 20- 30 years your return on investment would be over $300,000- $450,000. In this light I believe borrowing to invest in your own career, intellectual advancement or greater business income whilst still a debt, it’s definitely a better debt than a worse one.