Which of the following is true about non-conforming uses of land?

Non-conforming uses of land refer to properties that were legally established according to the zoning regulations in place at the time but do not comply with new zoning laws. The key aspect of non-conforming uses is that they are permitted to continue operating even though they no longer meet current zoning requirements. This continuation is based on the principle of allowing existing uses to remain in place to avoid imposing undue hardship on property owners who invested in those uses legitimately before the zoning changes.

Therefore, stating that non-conforming uses may continue as long as they were allowed at the time of establishment is accurate. Typically, these uses are protected under "grandfather" clauses in zoning ordinances, acknowledging that the property was in compliance when established, even if subsequent regulations change. This ensures that individuals are not penalized for changes in laws that occur after they have made investments in their properties.

The other options do not accurately reflect the nature of non-conforming uses. For example, non-conforming uses can often be sold or transferred, they do not have unconditional protection under all circumstances, and there is generally no requirement for restoration to conforming use within a specific timeframe unless mandated by local regulations.