Tried-and-tested troops who they have the utmost trust in and have delivered success in the past means reunions are fairly frequent in football.
Just look at former Pompey boss Harry Redknapp with Peter Crouch and Niko Kranjcar, for example.
Look at when Paul Cook arrived at Fratton Park in the summer of 2015 and ensured Gary Roberts followed him from Chesterfield.
It’s a recruitment policy that Danny Cowley could also look to implement during his Blues summer overhaul.
In truth, it wouldn’t be a surprise if any of his former players from his time managing Lincoln and Huddersfield who’re available join him.
Cowley’s put the free agent market to good use so far, swooping for Clark Robertson (Rotherham), Shaun Williams (Millwall) and Ryan Tunnicliffe (Luton).
But who are some of the head coach’s ex-troops currently without a club and he could be tempted to move for.
We’ve taken a look...
9. Jake Hesketh
The attacking midfielder was signed by Cowley in September 2019 after their promotion to League One. However, Hesketh did not play once for Cowley at Sincil Bank as he left for Lincoln a week later. Hesketh made 24 outings for Michael Appleton but was limited to 17 appearances for League Two Crawley last season. Photo: Harry Trump
10. Ryan Allsop
The keeper's not the most popular in these parts, having been drafted in on emergency loan for Pompey's League Two play-off semi-final second leg loss at Plymouth in 2016. However, Allsop did make 20 outings for Lincoln in the 2017-18 season. The ex-Bournemouth man also helped Wycombe clinch promotion to the Championship two seasons ago but was released after their immediate relegation. Cowley's mulling over another goalkeeper but it'll likely be a younger one. Photo: Catherine Ivill