If someone partially performs a contract, do they still get paid?

Yes, under substantial performance doctrine—if the performance is substantial enough that it achieves the contract's core purpose. However, they're liable for damages caused by the shortfall. Courts weigh whether the deviation was minor (contractor used equivalent materials) versus material (entire project direction changed). This is why contracts should explicitly define what constitutes acceptable performance variance.

How does time is of the essence change performance rules?

If a contract includes "time is of the essence," late delivery typically constitutes material breach, voiding payment rights entirely. Without this clause, courts are more forgiving—treating delays as minor breaches subject to damages rather than termination. Always clarify timeline criticality in contracts to avoid disputes about whether a delay killed the deal.

What's the difference between performance and payment?

Performance is completing the work; payment is compensation for performance. A vendor can perform perfectly but remain unpaid if payment terms haven't been satisfied. Conversely, a customer can pay but refuse to accept substandard performance. These are separate obligations—performance doesn't automatically trigger payment unless the contract says so.