This is essentially a records retention question - there are a number of tax-related AND business-related documents that any business should retain, the eternal question is "for how long"?

There is no statute of limitations on tax fraud. In theory, the IRS or your state (if you live in an income tax state) can audit your records indefinitely. If your business receives Federal assistance of any kind (FEMA payment, SBA loans, Federal contract, tax credits, etc) your exposure never really expires. But practically speaking, even the largest municipal utilities have records retention schedules that rarely extend beyond ten years.

But if you have bought business real estate and have made improvements, THOSE records have to be kept at LEAST until you sell, for capital gains accounting purposes, and then many years thereafter in case of audit.

On the other hand, if you label your file folders, put them into labeled boxes, and keep a list of the boxes and the folders inside each box, it can take 20 years to fill up a 6x6x8 foot high personal storage bin. Isn't it worth the modest cost of the storage to keep your old stuff just in case?

If it is not worth it to you, then you can safely discard all but your long term asset documents after about ten years.