Were such a thing as a Magna Carta of football management to exist, you probably wouldn't get very far into the tome before coming across the decree that you don't change a winning side.
With the Scottish Cup second round tie with Cove Rangers looming, Vale decided to rest several key players, but chalked up their tenth straight win at Riccarton regardless.
A quiet opening spell saw both teams pass the ball around attractively, without showing much of a cutting edge, but Vale were shaping up as the most threatening of the two teams and broke the deadlock in the 36th minute.
It was rough justice for the home side as a free kick from Chris Donnelly appeared to hit off an arm in the Vale defensive wall, leading to loud appeals for a penalty, but the Innerleithen side immediately broke upfield with Jamie Lauder slipping a ball into the path of Jordan Hall, who took a few strides into the penalty area before finding the corner of the net.
But the teams went in level at the break, as Heriot-Watt equalized with four minutes of the half remaining, Michael Connor squaring a ball into the middle for Gordon Wilson to side-foot home.
The outcome was ultimately decided with a blistering opening to the second half by Vale.
Three minutes after the restart, Scott Devlin launched a ball into the penalty area, where Scott Moffat rose to place a header into the net.
Five minutes later Moffat was on target again, knocking home a Hall cross to put Vale firmly in control.
Watt pulled another goal back in the 70th minute, as young midfielder David Myatt produced a composed finish, despite appeals for offside by the Vale defence.
But Vale restored their two-goal lead just a couple of minutes later, Ferguson picking up the ball wide on the right and superbly holding off the challenge of Watt defender Gavin Main before sending a fine strike into the far corner of the net.
Vale of Leithen: M. Wilson; C. Beaton, J. Lauder, R. Miller, G. McNicoll (P. Lee 40), S. Devlin (P. Greenhill 76), S. Sproule, J. Paterson, S. Moffat (S. Radzynski 76), J. Ferguson & J. Hall.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here