For many in the Massachusetts state Senate, the sales tax holiday must feel like a bad penny. Try as they might to lose it, the idea keeps turning back up. Senators should take heart, however, and deem this next opportunity to schedule a tax-free weekend as one of those rare chances to fix past mistakes — a legislative do-over.

Their fellow lawmakers in the House have ornamented an economic development bill with a two-day reprieve from the 6.25 percent sales tax, scheduled for the weekend of Aug. 11-12. The Senate should embrace the holiday in its own version of the bill, giving a break to back-to-school shoppers and a boost to businesses along the border with tax-free New Hampshire for the first time in three years.

That would mean changing their minds, of course. It’s barely been two months since the Senate rejected a tax holiday for this year by a vote of 24-14.

A lot has happened since. Lawmakers, business groups and labor interests struck a “grand bargain” to get in front of ballot questions that would have permanently created a tax holiday, raised the minimum wage to $15 per hour, and mandated paid medical leave for workers. While the deal instituted all of those things — with some important tweaks — it regrettably didn’t schedule the next two-day tax break until 2019.

House Speaker Robert DeLeo said last weekend he would fix that, and earlier this week his colleagues voted accordingly.

Forgoing two days of taxes isn’t a benign gesture for the state, which loses out on some $20 million worth of expected collections. That’s the reason lawmakers didn’t schedule the holidays these past couple of years, citing tough financial straits and ending a string of successful summertime tax holidays over the previous dozen years.

Squeezing a tax holiday onto this year’s calendar should be easier with the state well into the black. There are hundreds of millions more dollars in revenue in the coffers than projected.

Those are tax dollars, you know. So, while senators should schedule a tax holiday because it creates an economic spark during a slow season for retail, they also should do it because that extra money wasn’t really the state’s to begin with.