Williams has defended its decision to make Bruno Senna sacrifice practice mileage to Valtteri Bottas in 2012 after promoting the Finn to take Senna's place in the race team next season.
The Brazilian often struggled in qualifying and was dropped at the end of the 2012 Formula 1 campaign.
He ultimately sat out 15 of the year's 20 practice one sessions for Bottas. Team-mate Pastor Maldonado in contrast ran in all sessions.
Williams's chief operations engineer Mark Gillan is sure bringing Bottas in on most Fridays was sufficiently beneficial to the team.
Asked by AUTOSPORT if Senna's struggles made it hard to justify denying him practice mileage, Gillan replied: "It's a good question. It's one that we will look at in depth.
"It's a balancing act. It's something that we all knew at the beginning of the season and we did our best to mitigate Bruno missing FP1 and did our best to learn from Valtteri.
"Each driver has different feedback. Bruno is different to Pastor, Valtteri is very different to Bruno and Pastor, and we've learned from that a lot.
"Valtteri benefited tremendously from it. We have got a lot from the third driver as well."
Gillan argued that granting Bottas track time was also beneficial for Williams's development as it facilitated comparison between its simulator and the FW34.
"With Valtteri being in the simulator a lot, it's important that he's had track time so that our virtual simulation package can be pushed forward," Gillan added.