Of the many luxuries professional sportspersons enjoy, certainty is not one of them. That's why we hear them speak about playing every game as though it's their last, or in Kyle Abbott's case, their first.
Since Abbott became the second most successful South African bowler on Test debut - with 7 for 29 in the first innings against Pakistan in February 2013, behind only his coach Lance Klusener, who took 8 for 64 in 1996 - he has struggled, not to continue the sensation as anyone would, but to keep a regular place in the team and has admitted see-sawing in and out of the XI is starting to bother him.
"That has been the case since my debut - I didn't go on the next Test series after that so that's something I've had to deal with. It's not an easy position to be in but at the end of the day, you've got to tick your boxes on the field and let things take care of themselves. It is frustrating at times but there is nothing I can do about it," Abbot said after South Africa won the ODI series 2-1 against New Zealand in Durban.
Abbott was not due to play in that match, and would have been the only member of the ODI squad not to play a game in the series against New Zealand but a viral infection to Vernon Philander provided him with an opportunity to perform in front of his home crowd. He extracted some extra bounce, was economical and executed well at the end of the innings, which should be enough to keep his place but the reality is the next time South Africa take the field, in a month's time in India, Abbott is more likely to be out of the XI than in it. And he knows there is very little, in preparation or performance, he can do to change that.
"As long as I am happy with what I am doing off the field and giving everything to this team, opportunities eventually come. On the field, maybe I go in search of one [wicket] that I shouldn't but I guess I'm human at the end of the day," he said. "It is a tough situation but I've got my head around it over the last two years and learnt to deal with it."
Abbott has played three Tests - the first one as a replacement for an injured Jacques Kallis, which explains why Abbott was not retained afterwards, and the next two as part of a four-pronged pace pack. He had to wait more than a year after his first match to get a second, in March 2014, and then another nine months before South Africa chose to employ that strategy, to which they have not returned since, again. His second and third Tests were not as successful as his first but they could hardly have been expected to be.
The Test attack is settled as long as Dale Steyn, Philander and Morne Morkel are fit, so opportunities are hard to come by and Abbott tried to push for a place in limited-overs formats instead. It was not until the tour to Bangladesh last month that Abbott actually had the chance to play in a full series and that came on the back of a World Cup that would have taken an emotional toll on him in particular.
Abbott was picked as a reserve bowler in the squad but ended up being South Africa's most successful bowler in terms of strike rate and economy when he filled in for Philander, who was carrying a hamstring strain. But Abbott was embroiled in a selection controversy after he was left out of the semi-final XI in favour of Philander and it later emerged CSA CEO Haroon Lorgat consulted with coach Russell Domingo and then-convener of selectors Andrew Hudson and "impressed upon them the need to properly consider the best XI bearing in mind the transformation guidelines."
Everything seemed to go south for Abbott after that. At the World Cup he played four ODIs, took nine wickets at an average of 14.44 and a strike rate of 20.6, while conceding at 4.19 runs per over. After the World Cup he played four ODIs, bowled 25.2 overs, took two wickets at an average of 66.50, a strike rate of 76 and economy rate of 5.25. Conditions would have played some part in the disparity, confidence, or lack thereof, would have done the rest.
Suddenly, Abbott would have realised he may not be the very next person in line, especially as Kagiso Rabada leapfrogged him and all his efforts to assume the death-bowling role, and mastering the yorker permanently could have gone in vain. For now he plans on keeping at it, in the hope his fortunes will change.
"It's difficult bowling at the back, it's not fun sometimes but when it does come off and you suddenly go for two runs, or you pick up two and you go for three runs it feels pretty good," Abbott said. "It's something I have taken on. There's been a lot more down than ups at the time in the innings but I still think there is something around the corner and a couple of years of hard work and dedicating to those dirty overs in the nets is going to pay off. It might be in the next four or five months."
The next six months see South Africa embark on the busiest season in recent memory with their longest-ever tour to India and their first hosting of a four Test series against England, in more than a decade, culminating in the World T20. Abbott has no certainty about how involved he will be in those series. All he does know is that he wants to be part of them.

Firdose Moonda is ESPNcricinfo's South Africa correspondent