In his testimony yesterday, Kyle Sampson is reported to have said "I don't remember" 122 times (WaPo here). And keep in mind that his testimony was cut off in the fourth hour by Republican objections to the hearings continuing ... who knows how many times he would have said it if the hearing had run its course.
The segments I heard contained those exact words a few times and the Post has the string in quotes, but let's assume he did not utter that same phrase that many times. Still, even in media excerpts, you got a sense of worn repetition, of monotony. I can't imagine what the real thing felt like.
Under these circumstances, it surely would have been better to have a little stylistic variation: "I simply cannot recall", "Sorry, Senator, but my memory fails me", "The answer to that isn't coming to me right now", "My recollection on that point is not clear", "Oh for heck, my pants are on fire". (Even when he wasn't saying "I don't remember" about really major stuff, he seemed to be saying things that were surely lies.)
Makes you wonder what he was thinking strategically: "I'm badly burned toast and I can feel the flames of hell already. What does this matter?" "Well, everybody knows I'm lying sack of crap here, but the lawyers say I've got to keep up the charade." Note to self: Variation is good; a sound memory and avoiding dishonest activities much, much better.
Note: Image from a pretty amazing website: Mothers from Hell.