This Wimbledon has provided the perfect reminder that one bad performance and I'm out of the tournament.
I'm happy to say that for the second round running, my match was not the story of the day and the big news was being made elsewhere.
After Rafael Nadal lost on Monday, Sergiy Stakhovsky beat Roger Federer to show once again that you can run into someone playing the match of their life and, if you're not quite on it, you can lose. I played Stakhovsky in the final of the US Open juniors and he's a very talented guy with great hands and good feel.
It's another example of why every time you step on the court, you need to be ready and you need to be prepared.
When everyone else gets carried away with the draw and who might play who, I'll just concentrate on my matches and I was delighted to get past Yen-Hsun Lu in three sets and move another step forward.
There was certainly plenty going on elsewhere with all sorts of injuries and retirements, and this has just been one of those tournaments so far. Because of that, I was a bit tentative at the start of my match, but I didn't have any problems with the court and soon felt fine.
I don't know the ins and outs of everyone's injuries, but I do think players are quicker these days and grass is a tough surface to stop on. The way the guys throw their bodies around the court now, they seem to slip down more than they used to.
You can't move like that on a grass court; you need to be very particular with your foot placement and that's the thing that takes time to get used to coming from the clay. There you can be throwing your right leg into sliding for a ball; here you have to take small steps to slow yourself down or you'll fall.
We certainly saw a lot of retirements on Wednesday but it's hard to make any judgement about why that was, because as athletes you spend a lot of your time carrying injuries of one sort or another.
I'd say there are three categories: about 20% of the time your body feels great and you feel nothing; quite a bit of the time you'll have something that might be a bit sore, but it doesn't affect your tennis at all; the rest of the time you can be carrying something that means you have to compensate and make adjustments to your game. Everyone has to deal with it.
Playing at Grand Slams takes its toll because of the five-set matches; you have to do more training to play for five sets, which then shortens your career.
Playing for three sets requires a different sort of fitness - you don't really need the endurance, you just need to be quick and explosive for two or two and a half hours, whereas the endurance aspect comes into it in the best-of-five-set matches. But it's always been best-of-five in the Slams and I don't mind that - I'm used to it now.
That isn't an argument about men's and women's tennis, by the way, although I have been challenged by someone on Twitter to taking on Serena Williams. I'd be up for it, why not?
I've never hit with her but she's obviously an incredible player and I think people would be interested to see the men play against the women to see how the styles match up. It's happened in the past with Jimmy Connors and Martina Navratilova. How about Las Vegas as a venue?
For now, I'm totally focused on Friday and playing Tommy Robredo in the third round.
He's a top player, very experienced and he came back from two sets down three times in a row at the French Open, so I know he'll fight until the very last point.
I'll prepare by practising with Kyle Edmund, the British junior, as I hit with him a couple of days before the tournament and he's a good guy. Then I'll do all my physio and my fitness work and, if I can get through on Friday, I know I've then got two days off to recuperate.
That might give me a chance to take the dogs for a walk, as I don't see them during the day and by the time I get home they're pretty tired. I think their TV appearance last weekend must have exhausted them, although they haven't turned into complete divas yet.