There has been a lot of talk about using reconciliation lately. What is important is that reconciliation measures by law face only limited debate in the Senate, so, as a result, can't be filibustered. Reconciliation measures can pass with a simple, Constitutional majority vote. Part of the what governs reconciliation is the Byrd rule. These are a set of parameters for what can and can't be part of a reconciliation measure. Effectively every provision in the bill must affect the budget, or it can be removed by the Byrd rule. In theory, this very much restricts what reconciliation can be used for, but the decision of how to apply the Byrd rule is ultimately up to Joe Biden.
What is important is whose job it is to decide if a provision runs afoul of the Byrd rule. The Senate parliamentarian’s role is to make the determination and advise the presiding officer of the Senate, normally the Vice President, on how to rule. By tradition, the presiding officer essentially always rules in accordance with the parliamentarian's advice, but technically the final decision is completely up to the presiding officer.
Normally, a senator raises a point of order, saying a provision in the reconciliation bill violates the Byrd rule. Assuming he or she agrees, the parliamentarian makes a determination, and tells the presiding officer that it does violate the Byrd rule. The presiding officer normally rules in accordance with the parliamentarian’s advice, and sustains the motion. The provision would be removed, unless 60 senators vote to waive the Byrd rule for that provision, allowing it to stay in the bill. Under reconciliation, it takes 60 votes to waive a point of order or overturn the chair's ruling against a point of order.
As the presiding officer of the Senate, VP Joe Biden does not need to follow the advice of the parliamentarian. During debate on a reconciliation bill, he has the power to reject every point of order made about a provision that might violate the Byrd rule. And, if he did, it would take 60 votes to overrule him and remove the provision. Ultimately, Joe Biden could decide that nothing, or almost nothing, runs afoul of the Byrd rule, and allow practically anything to pass the Senate using reconciliation and a simple majority vote.
This would be a violation of Senate tradition re: reconciliation and the Byrd rule, but it is still technically allowed under a strict interpretation of the rules. It is important to remember that the “tradition” of reconciliation only dates back to its creation in 1974, and the Byrd rule was created in 1985.
Of course, the Republicans have decided to use a strict interpretation of the rules governing debate to violate Senate tradition by creating a de facto supermajority requirement for ever piece of routine business. If the Republican are willing to play hardball by with the Senate rules by filibustering everything, the Democrats have no other option but to respond in kind.
Using reconciliation for everything is not a perfect solution--ideally, the Senate would function according to the Constitution, and allow a simple majority to pass legislation through regular order. But If Democrats were willing to match Republican hardball tactics with hardball tactics of their own, they can technically use reconciliation to pass almost any law they want with a simple majority.
For more information on reconciliation and the Byrd rule, you can read the following Congressional Research Services report.