It's about three-tenths as long as The Revolutionary War (American)
In other words, 30 months is 0.29820 times the length of The Revolutionary War (American), and the length of The Revolutionary War (American) is 3.3530 times that amount.(a.k.a. American War of Independence) (1775-83)
The War between Great Britain and the its thirteen colonies in North America (now the United States) for the independence of the United States is generally considered to have started with the Battle of Lexington and Concord on April 18th, 1775 (sometimes known as "The Shot Heard 'round the World") and to have concluded with the signing of the Treaty of Paris on September 3rd, 1783 — 100.60 months. A total of 25,000 Americans are estimated to have died as a result of the war.
It's about one-fifth as long as FDR's Presidential Term
In other words, 30 months is 0.20630 times the length of FDR's Presidential Term, and the length of FDR's Presidential Term is 4.8470 times that amount.(a.k.a. Franklin Roosevelt, a.k.a. Franklin Delano Roosevelt) (1933-45)
FDR, the 32nd President of the United States, served from March 4th, 1933 to April 12th, 1945, dying after 145.40 months in office. At the time of his sudden death, Elizabeth Shoumatoff was painting a portrait of Roosevelt which, never finished, now hangs in a museum at the site of Roosevelt's Presidential retreat in Georgia.
It's about eight times as long as The First artificial heart patient's survival
In other words, 30 months is 8.140 times the length of The First artificial heart patient's survival, and the length of The First artificial heart patient's survival is 0.1230 times that amount.(1982) (Dr. Barney Bailey Clark; first permanent, pneumatic device)
On December 2nd, 1982 Dr. William DeVries implanted the first artificial heart into Dr. Barney Bailey Clark, who went on to live for 3.680 months. This early model of the artificial heart was controlled and powered by an external, 146.51 kg (323 lb) machine that Dr. Clark had to cart with him as he moved throughout the hospital.
It's about eight-and-a-half times as long as The Spanish-American War
In other words, 30 months is 8.370 times the length of The Spanish-American War, and the length of The Spanish-American War is 0.1190 times that amount.(1898)
The War between Spain and the United States over the liberation of Cuba began on April 25th, 1898 and lasted until the signing of the Treaty of Paris on August 12th, 1898, 3.550 months. The Treaty gave the United States control of Cuba, the Philippines, Puerto Rico, and Guam.
It's about ten times as long as Columbus' voyage to America
In other words, the length of Columbus' voyage to America is 0.10 times 30 months.(1492) (first voyage)
Attempting to find a western route to Asia, Christopher Columbus set sail on August 3rd, 1492 and landed in the Bahamas on October 12th — 2 months later. After one of Columbus' ships, the Santa Maria ran aground in present-day Haiti, he ordered that the timber be used to used to build a fort and settlement called La Navidad; it remains missing to archaeologists to this day.
It's about ten times as long as The First spaceflight (Sputnik)
In other words, the length of The First spaceflight (Sputnik) is 0.10 times 30 months.(a.k.a. Sputnik 1, a.k.a. Спутник-1, a.k.a. "Satellite-1", a.k.a. Простейший Спутник-1) (1957) (total time in orbit)
Launched from Kazakhstan in 1957, Sputnik was the first artificial satellite placed into orbit around Earth, where it remained for 3 months. During its voyage, it traveled about 70,000,000 km (43,495,983.46 mi), completing an orbit of the planet every 0.0022 months.
It's about one-fifteenth as long as Pius IX's reign
In other words, 30 months is 0.07894 times the length of Pius IX's reign, and the length of Pius IX's reign is 12.670 times that amount.(a.k.a. Pope Blessed Pius IX, a.k.a. Giovanni Maria Mastai-Ferretti) (1792-1878)
The longest reigning Pope in the Church's history, Pius IX reigned from June 16th, 1846 to February 7th, 1878 — 380 months. As the last monarchical Pope, he ruled over 3,000,000 subjects in the Papal States until 1870.