Tax sales are a balancing act among (1) the need of government to collect property taxes and, if owners will not pay then, then to provide incentives for investors to purchase the tax rights and (2) investors, who need an attractive return for the risk they are taking, and (3) citizen taxpayers, who should not lose their property and all equity because of small debts and perhaps temporary or at least relatively short term financial difficulties.

What if annual tax payments were made to keep it from going back to auction?

Maybe they cater to the government and are used to just spending tax payers money with no responsibility. 

This form includes their name, address, and Taxpayer Identification Number (TIN).2.

In the past, smaller taxpayers such as yourself held a disproportionately higher audit risk since it's a lot faster to audit the little guy which makes their numbers look better.

Here is the summary if you are interested.In this case, the main question is when did the investor completed his start-up phase and became actively engaged in his business.Whether a taxpayer is engaged in a trade or business is determined using a facts and circumstances test under which courts have focused on the following three factors that indicate the existence of a trade or business: (1) whether the taxpayer undertook the activity intending to earn a profit; (2) whether the taxpayer is regularly and actively involved in the activity; and (3) whether the taxpayer's activity has actually commenced.

To qualify for ANY tax exclusion under IRC section 121, the taxpayer must convert to principal residence use hand hold for an additional three years (so the holding period is no shorter than five years).

i find ones who honest up front and honesty is confirmed by paperwork ate usually pay rent consistently  but anyone on taxpayer funded a long time or who have been evicted prior are more "dangerous" more likely not pay rent  than any felon.3. 

Plus, you'll be changing tax payers right before a sale and 1031. 

Timing of payment will depend on if you are required to make estimated tax payments.