The IRS has delayed tax day until May 17 this year because of the pandemic. That gives many taxpayers extra weeks to file and to pay tax owed. Not all taxpayers get extra time, though, and filing by mid-April may still make sense.

“Treasury’s decision to push the federal filing deadline to May 17, welcome as that may be for many taxpayers, has created some challenges for many,” said Christian Burgos, managing principal and state and local tax practice co-leader in the New York office of Friedman, LLP.

So far, the postponement generally covers just filing the 1040 series of returns and related schedules. Those who pay quarterly taxes must still file and pay federal taxes by April 15. Trusts, corporations and partnerships must also file then. “Same for the filing of gift tax returns,” added Richard Shapiro, tax director at EisnerAmper LLP in New York.

Accounting groups have advocated for an even longer filing delay. Recently, a bipartisan group of Congress members also asked the IRS to give those who pay estimated tax more time to file—and to pay. “The IRS commissioner has expressed that many wealthy individuals do not make their estimated payments and should not get a break on interest and penalties,” Shapiro said.

Keeping the April deadline can complicate quarterly filing, which has a payment safe harbor based on a previous year’s return. Such taxpayers often pay extra with the filing of their annual return as a hedge against underpayment and penalties for quarterly taxes.

But “how can one figure a 2021 estimate without getting good numbers for the 2020 tax return?” said Harlan Levinson, a CPA in Beverly Hills, Calif. “Once clients hear the deadline is May 17, it’s near impossible to get all of them that do quarterly estimates to get me their documents in time to get things figured for an April 15 payment.”

Added Gail Rosen, a CPA in Martinsville, N.J., “I file for a client May 17 and apply an overpayment from 2020 to first quarter of 2021. The IRS is going to deem that overpayment applied to the first estimate to be a month late.”

Additionally, taxpayers who may still expect to receive a federal stimulus payment may consider the timing of the filing of their returns. “If they’re expecting to report more income in 2020 compared to their 2019 return, they may consider holding off [filing] to maximize their stimulus payment,” Burgos said. “If a taxpayer plans to report less income in 2020 ... they may want to consider filing their return as soon as possible.”

“Given the recent changes and the Economic Impact Payment 3 guidelines, the extended time does allow for additional tax planning, which has become more necessary than ever before,” added Twila Midwood, enrolled agent at Advanced Tax Centre in Rockledge, Fla. “Certain married taxpayers filing jointly may benefit from filing separately this year. Filing separately may generate a higher tax liability on their 2020 return, [but] by doing so they may be eligible for EIP3 or take advantage of new child tax credit rules.”

State filing deadlines are another wrinkle “because states don’t automatically follow federal changes,” added Scott Hoppe, founder at Why Blu, a San Francisco accounting firm. “Of the 43 states with income taxes, a few have not moved from April 15 and some have moved to dates different from May 17.”

Last year also brought federal tax changes that some state legislatures have yet to fully address. “My biggest problem is whether California will conform to federal [Paycheck Protection Program] rules,” Levinson said.

When should taxpayers file, given the extra time? “For those getting refunds, it makes sense to file as soon as possible,” said Rob Seltzer, a CPA at Seltzer Business Management in Los Angeles. “On the other hand, if you owe, there’s no incentive to do so.”

“Because of the demands on the IRS with the recent legislation, you want to get in line for your refund now to avoid possible delays,” Hoppe added.

“Hold the cash and earn a little extra return on the money eventually being paid to the IRS,” Shapiro said.