(CNN) Rebuilding after a natural disaster -- a hurricane, flood, tornado, wildfire -- can take years, or a lifetime, even. Sometimes, things are never the same.

But in the immediate aftermath, financial and physical aid provided by the Federal Emergency Management Agency is crucial to recovery. Areas in south Texas, Florida and Puerto Rico are still reeling from the impact of three major hurricanes this season, and FEMA is already preparing for the long haul.

However, some recent comments by President Donald Trump seem to suggest the presence of FEMA workers and the availability of disaster relief funding could be curtailed in Puerto Rico, where a majority of the island's 3.4 million US citizens are dealing with contaminated water, power outages and severe infrastructure damage from Hurricane Maria.

"We cannot keep FEMA, the Military & the First Responders ... in P.R. forever!" Trump tweeted Thursday morning

How long does FEMA stay in disaster areas, and what kind of staffing does it bring? When the boots on the ground are gone, what kind of influence or aid remains?

Puerto Rico

Puerto Rico was hit by Hurricane Maria on September 20, 2017.

Federal staff deployed as of October 12, 2017: 5,200

There are are roughly 5,200 federal employees assisting recovery efforts in Puerto Rico, a FEMA official said. Eight-thousand Department of Defense personnel and 3,200 National Guard members have also been deployed.

Total public assistance grants: $ : $ 37,005,951.78

Total Individual & Households Program dollars approved: $43,258,814.89

How long they will stay: Years

The FEMA official said there is "no hard deadline" on phasing out efforts on the island, and stressed the difference between the "response" phase, which happens directly after a disaster, and the "recovery" phrase, which begins when immediate needs, like power and clean water, have been restored. The recovery phase, FEMA said, will most likely take years.

"While no recovery lasts forever, our focus is the response and we will continue to support the response. There's no indication of any immediate change until the situation is stabilized on the ground," the official said.

Texas

South Texas and parts of Louisiana were inundated with wind and record rains from Hurricane Harvey over the course of several days at the end of August 2017.

Federal staff deployed as of October 12, 2017: 3,900

Total public assistance grants: $ : $ 327,886,760.25

Total Individual & Households Program dollars approved: $1,065,882,028.55

How long they will stay: Years

"FEMA is going to be there for years," he said.

As with Puerto Rico, Long said the agency was focusing first on response, but was also looking at "pushing forward" with recovery aid like housing and flood insurance.

Florida

Parts of south Florida were severely damaged by Hurricane Irma, which slammed the state on September 10, 2017

Federal staff deployed as of October 12, 2017: 3,000

Total Individual & Households Program dollars approved: $737,939,690.57

How long they will stay: Years

New Orleans

Hurricane Katrina was the deadliest hurricane to hit the United States, and it is perhaps the most important touch point for federal disaster relief in recent years.

Federal staff deployed: 8,000+

As many was 7,333 disaster assistance employees were deployed at the height of FEMA's post-Katrina relief efforts . An additional 1,000 permanent FEMA employees were deployed, as were 200 on-call response and recovery employees.

Total public assistance dollars approved: $ : $ 13,430,039,697.20

Ten years after Katrina, FEMA had provided more than $15 billion for public works projects in the four Gulf states affected by the storm. These projects included the repair and rebuilding of roads, schools and buildings. FEMA provided an additional $6.7 billion in recovery and aid to more than 1 million people and households.

How long they stayed: They're still there.

Twelve years after the storm, the Department of Homeland Security and New Orleans residents are still at odds over funds promised to the city for infrastructure repair that still needs to be completed. So, although thousands of FEMA employees may not be lingering in the city, the presence of the agency, and the continued need for assistance, shows how long the timeline could be for more recently affected areas.

Indeed, the FEMA official who provided CNN with information on the Puerto Rico plan says the agency still works with Louisiana to this day.