Durability of the weapons may depend on the user's will.
How long the blade lasts depends on the users skill and power, some may need near constant attention, others are effectively permanent.
Wielders of the Falchion (Fire Emblem series)
Ryu Hayabusa (Ninja Gaiden series)
Falchion (Fire Emblem series)
Dragon-scaled Tessaiga (InuYasha)
Dragon Sword (Ninja Gaiden series)
Dark Dragon Blade (Ninja Gaiden series)
Marth (Fire Emblem series) is one of the wielders of the Falchion, which is highly effective against dragons.
Lucina (Fire Emblem series) is one of the weilders of Falchion, which is highly effective against dragons.
Tōshū (InuYasha) wielding the Dakki, a sword crafted from a dragon-demon's scale, which can drain demonic life energy.
After breaking the yōkai sword Dakki, Inuyasha's (InuYasha) Tessaiga became the Dragon-Scaled Tessaiga, which allows him to drain demonic energy with each slash.
Ryu Hayabusa (Ninja Gaiden series) possesses the Dragon Sword, a weapon carved from the fangs of one of the Divine Dragon Deities and can be infused with the power of the Eye of the Dragon. The sword can only be wielded by the strongest and spiritually pure of mankind.
When he raided the Hayabusa Village, Doku (Ninja Gaiden series) obtained the Dark Dragon Blade, a powerful blade forged from the bones of the Dark Dragon. The blade is able to gain power from each killing and gather the hatred and evil of mankind as power for the wielder, turing them into the Devil Incarnate.
After aquiring the Dark Dragon Blade, Murai (Ninja Gaiden) was turned into the Devil Incarnate, gaining incredible speed, strength, and became able to posses the power of the Dark Dragon.