Continuity mistake: When Anakin runs and jumps off the platform as it descends the lava bank, the glove is on his right hand, but in the next shot when he lands on the DLC-13 mining droid, the glove is suddenly on his left hand instead. (01:57:53)
Other mistake: When Obi-Wan drops the block on the MagnaGuards, the one sticking out still has his photoreceptor on his chest. When Obi-Wan cuts his head off, he should still be able to move because he still has the photoreceptor. MagnaGuards were specifically designed to be able to fight without their heads. (00:57:53)
Revealing mistake: When Anakin and Obi-Wan are fighting on the big table, in the wide shot where Obi-Wan kicks Anakin for the second time, you can see that the one who performs the kick is not Ewan McGregor, but his stunt double. When Anakin lands on the table in the next shot, the one left standing is also McGregor's stunt double, and this time he is even wearing a brown bandanna that Obi-Wan does not wear. (01:51:15)
Continuity mistake: When Anakin, Obi Wan and Palpatine are brought to General Grievous, as they are walking in just as Grievous says "ah yes" Anakin and Obi Wan turn to the left while Palpatine stands a little away from them. When Grievous says "General Kenobi, we've been waiting for you" Anakin and Obi Wan are turning left again.
Continuity mistake: The emperor sits up as he's using force lightning on Mace then a few seconds later he sits up again.
Continuity mistake: As Palpatine stands to face the Jedi, his right hand starts to turn around for his lightsaber. In the close up, his hand turns around again.
Continuity mistake: During the fight scene between Obi-Wan and Grievous, Grievous has the lower half of his left hand and upper half of his right hand severed during the saber duel. However, as he gets into his vehicle, the damage done to his right hand reverses itself and he is missing the lower half instead.
Answer: Darth Vader has a special chamber in which parts of the suit can be removed for comfort. When he is not in the chamber he must wear it at all times in order to survive.