There's a mechanic that I like from the first edition D6 Star Wars roleplaying game. I think its useful for Traveller.
Let's say that you've got a big job, like fixing the Jump Drive. The Ref sets a target number. Let's go with 24.
Obviously, you can't throw 24 on 2D +mods in classic Traveller.
Players get three rolls. Each time increment is increased exponentially. The first check may take 15 minutes. Something like a fuse needed to be replaced, if it succeeds against the target.
The second roll takes a day.
The third and final roll takes a week. (or 3 days...whatever the Ref thinks is appropriate).
Let's say the mod is +2 per level of Engineering skill. Our PC Engineer has Engineering-2. So, he's throwing 2D +4.
He throws a 7 +4 = 11 for the first throw. The problem can't be fixed in 15 minutes.
But, now, the Engineer understands more about the problem, and the target number is reduced. 24 - 11 = 13.
Now, the Engineer has a chance to complete repairs in a day if he can roll 13+ on 2D +4.
Yet, he rolls 4 + 4 = 8. No. There's a problem. He can't fix the Jump Drive in a day. If he spent a week, then maybe he could, but it's not fixed yet.
Still, the job got easier. 13 - 8 = 5.
Maybe the Engineer had to craft a part he didn't have, and that took most of the time. But, the ship will be fixed within the week as a 5+ is automatic on 2D +4.
I think that's a very neat mechanic.
EDIT: D6 1E Star Wars uses these time increments: 15 minutes, 1 Day, 2 additional Days (for a total of 3 Days). After that, no more repair rolls are allowed. The item is just broken and just needs to be replaced. Or, the Ref can allow something to change about the repair. A starport dock is needed. A part is needed that the ship's engineer cannot fabricate and doesn't have a replacement part in storage on the ship.
This can be turned into a device to use for adventuring in the game. The gravitics are out, let's say, and the crew is floating around with no artificial gravity. The ship's engineer did his three repair rolls over three days and is unable to fix the gravitics dumyflatchy that is burned out.
Now, the ship has to go after this part would only be available at Class C or better starports. Yet, when the ship finally gets to a Class C ports, they're out of the part, too! (Sounds like what happened in The Phantom Menace).