Home advantage matters in these local affairs.
They matter even more when the IRFU's Player Welfare Policy implies Leinster have to be careful in the use of their Ireland internationals.
This is the stick that comes with the carrot of producing players, like Garry Ringrose, Devin Toner and Josh van der Flier for the national team.
All three have presumably been re-routed for Ulster.
The fact Toner has been reserved for New Year's Eve points to a potential 'clash of the titans' with Franco van der Merwe in the air.
However, the undeniable strength in depth of Leinster means they are able to field eight men capped by Ireland, in addition to Zane Kirchner and captain Isa Nacewa.
The immediate sense is that coach Leo Cullen may go after Munster at the scrum where the selection of Cian Healy, James Tracy and Tadhg Furlong appears to put down a marker in that area.
First things first, Leinster will target a minimum five points from these two mouth-watering matches.
The big game temperaments of centre Rory O'Loughlin, wing Barry Daly and second row Ross Molony will be tested.
Cullen makes ten changes from the side which swatted Northampton Saints in The Champions Cup last week.
Certainly, the pairing of Ross Byrne and Jamison Gibson-Park at half-back is an interesting prospect. No stranger to this type of environment, Gibson-Park appears to be a cool customer as evidenced by his work in behind TJ Perenara on the Wellington Hurricanes way to the Super Rugby title in July.
The likeable Byrne is not exactly short of confidence ahead of the biggest test of his career.
This 21-year-old's skills are more akin to the man he will be facing, Tyler Bleyendaal, than Joey Carbery, the man who moved ahead of him in pre-season.
"People are going to judge me straight away, after one game or a half or whatever it is," he said.
"Whether you play well or you play badly, you just have to move on and try to improve again.
"Ultimately, I just have to do what I do best and keep getting better."
Byrne is a fine game-manager in the mould of a young Jonathan Sexton and his gifts are, arguably, more suited to dealing with what Munster will bring.
It is not as if he is being thrown in cold.
"It's been a steady transition," said Byrne.
"I played the Zebre game and then the Scarlets game, so it's not as if I hadn't been playing at all."
The removal of Leinster's Ireland internationals even worked in his favour during November.
"I had those games under the belt and I had been training with the lads away with Ireland. I was the only ten in training and getting loads of reps in."
Therefore, the European Cup back-to-back matches weren't too much of a shock to the system.
"From that perspective, it was great. My confidence was high. I was training well and I knew the plays exactly.
"It wasn't too big a step up." It will be interesting to see whether Nacewa will hand over the kicking tee to Byrne from the start.
While this is an area better termed a'work in progress' for Carbery, it is a strength of Byrne's, one he could derive confidence from.
Munster Director of Rugby Rassie Erasmus has decided to hold fire on All Black Francis Saili, restricted to the bench.
Their half-backs Conor Murray and Bleyendaal drive Munster's game forward. It could just come down to who wants this one more.
A rejuvenated Munster are rarely beaten in those circumstances.
Munster: S Zebo; D Sweetnam, J Taute, R Scannell, R O'Mahony; T Bleyendaal, C Murray; J Cronin, N Scannell, J Ryan, J Kleyn, D Ryan, P O'Mahony (capt), T O'Donnell, CJ Stander.
Leinster: Z Kirchner; I Nacewa (capt), R O'Loughlin, R Henshaw, B Daly; R Byrne, J Gibson-Park; C Healy, J Tracy, T Furlong, R Molony, M McCarthy, R Ruddock, D Leavy, J Conan.