You've been tinkering with the side for the past few weeks, but you now have a confident group of players, eager and willing to go out and beat the same opponents again. And, because you understand the importance of momentum and continuity, you send them all out to do just that.
Not if you're Gregor Townsend you don't. Having watched his Glasgow Warriors side put one hand on the 1872 Cup with their 20-16 victory over Edinburgh at Murrayfield last week, Townsend has made 10 changes - eight personnel, two positional - to the line-up for tonight's return match at Scotstoun. Goodness only knows how sharp his axe would have been had the Warriors actually lost in the national stadium six days ago.
We will know by eight o'clock this evening if the changes he has made add up to an act of genius or sheer folly. Certainly, there was no overwhelming case for resting players, the entire squad having enjoyed an unexpected break when their pre-Christmas game against Treviso was postponed 12 days ago. Townsend, the player, liked to keep the opposition guessing, and it is clearly a trait that has been inherited by Townsend, the coach.
"We have a strong squad," he said. "These games are very important not just to our standing in the league but also to our players. I want to give opportunities for players to play in these games, so it is a strong team we are putting out."
In fairness, there is some method in Townsend's, er, selection. He has changed two thirds of a front row that coughed up a number of penalties in the scrum. He has brought Josh Strauss into the starting XV after the South African made a compelling case for himself as a second-half substitute at Murrayfield. He has brought back Ruaridh Jackson, who also looked sharp when he came off the bench. And he has taken advantage of the fact that Sean Lamont has made a speedy recovery from the ankle ligament injury he suffered against Ospreys a month ago, bringing the winger straight back into the team.
It is also true that Glasgow were chopped and changed throughout the first half of last season. That strategy established competition and depth in the squad, factors that were critical in their impressively strong finish to the season. Townsend knows that he will have to stretch resources to the limit during the forthcoming RBS 6 Nations Championship, and that he will also need to have his top players fit and firing as they enter the season's finishing straight.
Yet even he admits things have not been going as well as they did in the last campaign. "We have done very well defensively this season, but we did well in attack and defence last year," he said. "There are a few reasons we are not producing the rugby we did at the end of last season, a long list.
"One, weather conditions, this is when the weather is not great, the pitches are heavy and it is different rugby you have to play then from when the pitches are drier. We have not won enough ball compared to last year - our line out has not functioned as well. We have not been accurate enough when we have had opportunities; I think back to the Cardiff game in perfect weather conditions and we did not hold on to the ball. We know we have not hit our top game yet but are striving to do that."
There is another stark contrast with Townsend's first year in charge: Glasgow turned Scotstoun into an impregnable fortress last season, losing at home just twice during the PRO12 campaign - and not once after November. However, the battlements have been crumbling and Townsend acknowledges how crucial it is to stop the rot. Warriors have lost their last three matches - one of them in the Heineken Cup - on their own patch.
"It is very important," he stressed. "We look at the home and away games as similar and we have an excellent away record, but prior to that we had an excellent home record. It has been three home losses so this is an opportunity to put that right."
Inconveniently, Edinburgh coach Alan Solomons is also looking at tonight's game as the chance to make amends. To all intents and purposes, Edinburgh appeared to be coasting for the first 40 minutes last week, but the wheels came off spectacularly in the second half. Solomons is a measured, analytical and softly-spoken fellow, but even the most ardent animal rights activist would probably have understood his feelings if he had gone home and kicked the cat.
We have to assume that the moggy got off lightly since Solomons' selection is not the work of a man who has been gnawing table legs in recent days. In contrast to Townsend, the South African has made just one change to his line-up, handing the loosehead prop berth to Ally Dickinson instead of Wicus Blaauw, who has the consolation of a spot on the bench.
Explaining his reluctance to rip last week's teamsheet to shreds, Solomons said: "We only had ourselves to blame for not winning [last week's] game. We played well and you have to see the game in context, which is why they get another opportunity to show what they can do against Glasgow."