Pensioners could run out of cash by the age of 75, as a result of rule changes coming into effect in April, the charity Age UK has warned.
The new pension rules will enable those over 55 to take as much money as they like out of their Defined Contribution (DC) schemes, at lower tax rates.
Age UK said some people could use up their savings within ten years.
However, the government has said that everyone will be entitled to free and impartial advice on their pensions.
Age UK has issued a discussion paper, Dashboards and Jam Jars, which calls for pension providers to develop "jam jar" tools to help people understand the state of their pension resources, so they can handle budgets and control their money.
These tools could help pensioners decide how much money to take out of their pension each year, it said.
And people should also be able to see a "pensions dashboard", which would collect data from all their pension schemes, including their state pension entitlement, so it could be seen in one place, the report urged.
The charity based its calculations on a 65 year-old who has built up a pension pot of £29,000.
It assumed that the pot increases in value by 3% a year.
On that basis, it said someone withdrawing £3,000 a year from the fund would run out of money by the time they were 75.
Withdrawing £2,000 a year would mean the savings pot would disappear by the age of 81.
Age UK said it was also concerned about the level of administrative charges on pension funds, which can cut thousands of pounds from a pensioner's income.
"We welcome people having more flexibility in how to use their pension savings," said Caroline Abrahams, the director of Age UK.
"But that makes it even more important that we fully understand the implications and consequences of our financial decisions and can trust the financial services in which we have invested."
The government has defended the pension changes, saying savers should be free to spend their money as they see fit.
And from April 2015, annual charges on auto-enrolment pensions, which account for a large number of DC schemes, will be capped - at 0.75%.
The chancellor confirmed in October that free guidance will be provided by Citizens Advice and the Pensions Advisory Service.
The name of the guidance service is due to be announced next week.
However, Age UK says some people with small pension pots might not access the service, and for others there might be a "long gap" between accessing the guidance and using their pension to give them a retirement income.
Under the pensions changes, holders of DC pensions will be able to withdraw as much money as they like from their pots.
The first 25% will remain tax-free. Holders will be liable for income tax on the rest.
Age UK also wants more action taken against pension liberation scams, which encourage people to cash in their savings early.
Its report calls for the pensions industry to work with regulators, the government and the police to prevent scams.
"Pension providers' employees need to be trained to spot consumers who may be vulnerable to investment scams and to provide specific warnings," it says.
These often fall under the guise of "risky alternative investments [with] the promise that they are safe and will offer higher levels of income".
A Treasury spokeswoman said its "radical" pension reforms were intended to give retired people an increased choice of what to do with their money, and had been "almost universally welcomed by consumer groups and pensions experts".
She added: "The government believes that people who have worked hard and saved all their lives should have the freedom to decide how to use their savings and the guidance to help them make good decisions.
"We're delivering a guidance service to rigorous Financial Conduct Authority standards, which empowers and educates people so they can make their own, informed choices and confidently engage with the pensions industry."