From Air and Space's Dragonfly Is the First Aircraft Built for the Outer Solar System; NASA returns to Saturn’s largest moon with a rover that can fly. which I just found in this heavily-sourced answer to How does the Dragonfly helicopter for Titan compare to Perseverance, Ingenuity and a human in terms of size, mass, weight and daily range?
“Hopefully, we fly for years and years.” says Ralph Lorenz, an APL planetary scientist who was a member of the Cassini radar team and is Dragonfly’s mission architect.
And they'd certainly better!!!
In this April 2020 Assessments of Major NASA Projects GAO-20-405 on page 37, Dragonfly's science mission is listed as 2.7 years. (launch ~2026, landing 2034)
The well-sourced answer to the 2018 question How quickly might a Titan rover or drone get covered in oil and dirt? Will it need windshield-wipers? begins "Honestly, from what I can tell, not much consideration has been given to this issue." Three years later and a lot closer to a planned 2027 launch, there should be some additional thought and work on this.
Answers to Do Mars rovers protect optical windows during dust storms? Do they "avert their eyes" or do they just "grin and bear it"? address dust problems, but Titan is semi-literally a whole 'nuther ball of wax-like substances!
Detail from screenshot from the NASA video Dragonfly: NASA's New Mission to Explore Saturn's Moon Titan at about 00:44 showing plenty of nooks and crannies and small parts that might get dirty:
Ghostbuster and Bill Murray fans will remember what getting slimed means.
The findings of the Huygens probe indicate that Titan's atmosphere periodically rains liquid methane and other organic compounds onto the moon's surface. In October 2007, observers noted an increase in apparent opacity in the clouds above the equatorial Xanadu region, suggestive of "methane drizzle", though this was not direct evidence for rain. However, subsequent images of lakes in Titan's southern hemisphere taken over one year show that they are enlarged and filled by seasonal hydrocarbon rainfall. It is possible that areas of Titan's surface may be coated in a layer of tholins, but this has not been confirmed
I don't understand the chemistry of tholins, methane drizzle and ethane fog (mentioned in diagram below) but it doesn't sound like a place where you could leave a camera or other instrument outside for an extended period of time and expect the lenses and windows to stay optically clean and transparent without any attention to covering or cleaning.
If droplets of goo are hanging from the leading and trailing edges of the helicopter's propellors their aerodynamic properties will change as well. I wonder if they will have something like organo-phobic cotaings or "de-icing" technology for shedding, melting or vaporizing organic viscous liquids or solids?
How do they know that the Dragonfly helicopter won't get quickly coated in tholin muck? Will it have any muck mitigation or desliming technology?
A graph detailing temperature, pressure, and other aspects of Titan's climate. The atmospheric haze lowers the temperature in the lower atmosphere, while methane raises the temperature at the surface. Cryovolcanoes erupt methane into the atmosphere, which then rains down onto the surface, forming lakes. Source
left: Image of Titan's surface taken by the Huygens probe on 14 January 2005. (PIA07232) source From Wikipedia's Tholin: The surface of Titan as viewed from the Huygens lander. Tholins are suspected to be the source of the reddish color of both the surface and the atmospheric haze. and right: source The formation of tholins in the atmosphere of Titan