Pondering your end-of-life wishes probably is not typically atop your daily to-do list, especially if you're mid-career and more concerned about keeping up with food and shelter and education for yourself and, say, children still in the home.

But that time will come, and if you've invested well and saved wisely, you may be leaving behind a substantial remainder of your nest egg. Now's a good time to consider their challenges in managing your legacy.

We're not talking about leaving a will; we're talking about the complexity of your assets. The type of investments that are easiest to manage for people who inherit them will depend on such things as the size of the portfolio, individual financial goals and risk tolerance, and their level of investment knowledge and experience.

Plenty of very smart people don't know anything about stocks or the market and are happy to keep it that way, and that's OK. However, some types of investments may generally be easier for your heirs to manage, and some that aren't.

Here are four of each:

Four easy pieces

"I'd like a plain omelet, no potatoes on the plate, a cup of coffee, and a side order of wheat toast," Jack Nicholson's character says in the 1970 film classic Five Easy Pieces. We're going to keep it even simpler. Here are four basic investment types that your heirs can continue to profit from with minimal management and maintenance.

1. Index or exchange-traded funds: These are passive investments that track market indexes. There are many of them. You can choose a sector or simply the whole market, and history tells us that individual stock picks don't often beat the long-term performance of such stalwarts as the Vanguard S&P 500 ETF. This mammoth exchange-traded fund now has a market cap of nearly $300 billion and is currently yielding about 1.55% in dividend income, as well.

2. Bonds: Bonds are fixed-income investments in governments or corporations and can be less volatile than stocks while providing a steady stream of income. You can certainly buy Treasury notes and savings bonds on your own, but perhaps the easiest way for everyday investors to own bonds is through bond funds. A good example is the Fidelity Total Bond ETF, which tracks the Bloomberg U.S. Universal Bond Index and currently yields about 3%.

3. Mutual funds: Mutual funds are professionally managed pools of assets bundled as a single investment. They can offer diversification across various asset classes, carry a wide range of investment minimums and institutional or individual requirements, and are sold either as open-end or closed-end mutual funds.

They also can hold all bonds, all stocks, a mixture of both or other assets, and cash. One of the best-known examples is the venerable Fidelity Magellan Fund, which gained legendary status under the management of Peter Lynch.

4. Real estate investment trusts (REITs): REITs invest in pools of income-producing real estate and are required by tax law to annually pay shareholders at least 90% of taxable income as dividends. There are more than 200 publicly traded REITs across multiple sectors.

One of the most popular is Realty Income, owner of more than 12,200 properties in the U.S., U.K., Spain, and Italy. This dividend machine has paid its shareholders monthly without fail throughout its 54-year operating history and currently is yielding about 5.1%.

The best may not be for the rest of us, and that's OK

Arguably, the really big money is made in such areas as alternative investments such as private equity, hedge funds, and venture capital; options and derivatives; and direct real estate investments in all their forms.

That's OK if these are out of your reach because the fourth, of course, is individual stocks, which, while more accessible to the average investor than the first three, also require a lot of attention and expertise to truly manage successfully.

And those you're leaving the money need to know that it's important to consider seeking professional advice to ensure their investments are appropriate to their own goals, and skills, and attention levels -- at least until they're comfortable with managing assets on their own.