Here are three of the week's top pieces of financial advice, gathered from around the web:

Easy investing on the fly
"The golden era of personal financial apps is here," said Brian O'Connell at The Street. There are now scores of smartphone-first services that will help you make an investment, manage your budget, save money at the store, and more. One top choice is Acorns, which tracks your debit and credit card transactions in real time, rounds them up to the nearest dollar, and then transfers the change to an investment account. And you might want to download Personal Capital, which collects all your financial accounts — investments, credit cards, mortgages — and puts them into an easy-to-read dashboard. You can manage your investments with online tools and, if you have more than $200,000 invested, access help from two dedicated financial advisers.

The truth about the 'death tax'
President Trump and his family allegedly used suspect schemes to dodge millions in taxes on his father Fred's estate, according to a recent New York Times report. "So how many people actually pay America's federal estate tax?" asked Jacob Passy at Market Watch. Not many. Only 5,219 households in 2016 paid the 40 percent tax, which is levied on transfers of property after death. They gave the IRS $18.3 billion in taxes on estates valued at $107.8 billion. Even fewer will pay in the future. The 2017 tax reform package doubled the level at which the tax kicks in: Estates worth less than $11.2 million for individuals now escape the levy. But watch out for state estate taxes. Those kick in at lower levels, starting at $1 million in Oregon and Massachusetts.

Goodbye, planned obsolescence
There may be plenty of life left in your old iPhone, said Jeff Sommer at The New York Times. Apple made two recent decisions that could dramatically extend the life of your phone. One was introducing a battery replacement service, charging $79 to put a new battery in the old phone. The other was making sure the new operating system, iOS 12, would work on old phones as well as it does on new ones. This is the opposite of what we've come to expect: With previous updates, older phones would get slower. Not so now. With iOS 12, an older phone such as an iPhone 6 can open the camera app 70 percent faster and will run twice as fast under a heavy workload. "My old phone, which cost $649 new, seems like a much better deal now, considering all the use I'm getting out of it."