Depending on how many rental income properties you have and your experience with home improvement, you may be able to do a lot of the maintenance yourself. You likely won’t be able to fix everything but it will be worth it to learn a few common repairs to do yourself. Typically, plumbing and electrical maintenance will cost the most since work is generally restricted to licensed members of the trade unions.

Or you could do joint ventures/strategic alliances for your business or for other businesses and make residual cash flow for $0 investment.. that’s what I do lol. No money, no risk, little time, 20+ years working from home. Just connect companies and take a %, use the Internet to do it locally or globally, be the intermediary & connect companies…. ;-)
That depends what you call a “good” lifestyle. Could I rent yachts and get bottle service every weekend living off my passive income? No way. Could I travel 10–15 weeks a year and live in central Tel Aviv with money to spare? Definitely. I was able to earn low 6 figures completely passively. But if you want to make boatloads of money, and step up to the 7-figure territory, then yes, you’re going to need a combination. If, however, you want time to pursue your passions and have a moderate amount of fun, you can definitely sustain yourself with passive income. 

What's crazy is that my book income is more than my SF condo-rental income. Yet I didn't have to come up with $1.2 million of capital (the minimum cost to buy my condo today) to create my book. All I needed to create my book was energy, effort, and creativity. I truly believe that developing your own online product is one of the best ways to make money.

If you’ve ever thought to yourself, “I wish there was a product that did this,” then invent it! Create a product, medical or otherwise, and sell it as a company or get royalties for it. It’s not impossible to figure out, I have many friends who have taken a concept to market. Don’t overlook an invention as a fantastic means of attaining passive income.

* I use Personal Capital to track all my finances in one place. It’s much easier to use their free software to follow 28 accounts on one platform than to log into various accounts to check my balances. They’ve also got great tools for x-raying your portfolio for excessive fees, recommending a more optimized asset allocation, and planning for retirement with their Retirement Planner.