Manchester United need to ensure they strengthen their ranks both up front and in defence to make January a successful transfer window.
Last summer saw plenty of transfer activity as the squad was reshaped by Louis van Gaal. A goalkeeper, a defender, two midfielders and two forwards arrived.
And yet it was not enough.
The received wisdom was United needed an experienced, commanding leader of a centre-half. Since the gradual waning and eventual departures of Rio Ferdinand and Nemanja Vidic in 2014, United had looked increasingly uncertain at the back.
Van Gaal, rather than buying to strengthen at centre-back, instead took the option of assigning Daley Blind a new role within the squad. At the same time, Chris Smalling has stepped up and grown into his leadership role and has become the commanding, experienced centre-half the Red Devils needed.
Blind has, for the most part, done a very good job. There has been a problem, though, when injury has denied Van Gaal the rest of his first-choice back four. Luke Shaw's injury in September has had a hugely negative impact on United's season.
He was in fine personal form, added a great deal to United's attack and often had the energy and speed to cover for Blind on the occasions he was caught out of position. However, since Shaw's injury, things have been less certain.
Matteo Darmian, Antonio Valencia, Phil Jones and Marcos Rojo have battled with injuries of their own, meaning Ashley Young has often been drafted into defence. Blind has had to deputise at left-back, meaning Jones and Smalling have partnered up once again.
Jones' relentless injury niggles have meant momentum and solidity have been hard to come by for that partnership.
Van Gaal can address this in one of two ways.
Firstly, he can strengthen on either side at full-back, alleviating the need for Blind to be played elsewhere. Each position currently has a natural first and second choice in the squad—Darmian and Valencia on the right and Shaw and Rojo on the left, assuming Blind is playing at centre-back.
Beyond that, Blind, Young, Cameron Borthwick-Jackson and Darmian can all cover on the left. Young, Guillermo Varela, Paddy McNair, Jones and even Smalling—who played the position a lot under David Moyes—can cover on the right.
There are thus plenty of bodies to fill the roles but still plenty of doubts about quality in those spots. Inconsistency abounds. Darmian started the season in fine fettle but has often struggled. Similarly, Young looked very impressive against Swansea City on Saturday, but that was a relative rarity.
The other option Van Gaal has is to bring in a top quality centre-back, allowing Blind to cover Shaw's left-back position and leaving the right-back spot to Darmian.
Because Smalling has stepped into the role of the senior man and looks every inch the part, a promising younger central defender such as, say, John Stones of Everton could be called upon. Last summer, it seemed United needed a proven, top-level, established star. Now that need seems less pressing.
Ultimately, this seems the preferable option. Blind has plenty of strengths as a central defender but has limitations. Recently against Bournemouth, he allowed himself to get blocked off during a simple corner routine that allowed the Cherries ample room to score their winning goal.
His use of the ball remains superb, but his relative lack of speed means recovering from errors in positioning is a huge challenge. In spite of that, he is an asset to United, and some of the best football the side has played under Van Gaal came with Blind at left-back, where he could be redeployed in Shaw's absence if a new central defender were to arrive.
Whether through strengthening at full or centre-back, additional top-quality personnel in the back four could make a substantial difference to United. Their defensive record this season may have been impressive, but that has largely been down to a structure that has stifled both the opposition and United.
With better defenders, perhaps Van Gaal could relax his need to play two holding midfielders or at least allow those midfielders to break in front of the ball more often. That should, in theory, make United a more potent attacking threat.
Of course, another way to make United a more potent attacking threat would be to bring in a high-quality attacking player.
There is a need in terms of simple numbers to restock United's centre-forward ranks in particular. With apologies to Will Keane after his recall from an unsuccessful loan spell at Preston North End, United really only have two established centre-forwards on their books.
Anthony Martial has been a superb addition to the squad, and his impressive flexibility means Wayne Rooney can still be accommodated into the side. Memphis Depay's arrival has not been anything like the same kind of success—indeed, it is Memphis who is missing out in the starting XI at the moment in order to fit Martial and Rooney in.
If Van Gaal remains wedded to the inclusion of Rooney, then rather than an out-and-out No. 9, a player with similar flexibility to Martial would be the ideal choice. Back in June 2015, I argued Pierre-Emerick Aubameyang would be the ideal complement to United's squad.
In the middle of a highly productive season with Borussia Dortmund, Aubameyang has played almost exclusively through the middle, per WhoScored.com, though he, of course, has a history of playing as a wide forward.
There is the possibility a more traditional centre-forward could be brought in if Van Gaal were prepared to use Rooney more sparingly. He could also deploy United's captain at No. 10, though that has rarely been an effective option this season.
A mobile, technical, strong and clinical centre-forward is what would most fit the bill—a player such as Romelu Lukaku, for example. Given how often teams defend deep against United, speed and strength would be a huge asset in terms of creating space in which to operate.
Technical quality is vital in terms of contributing to United's pass-heavy build-up play, and a clinical edge is required given United create relatively few chances for their strikers at the moment.
A player like that is hard to come by at any time, but January is a particularly tricky time to dramatically improve a squad or, more specifically, a first XI.
Players playing at the top level are less likely to want to move as they are competing for silverware with their current clubs. Convincing new arrivals United are in contention for major honours this season would be a very hard sell.
It is vital United do not resort to squad filler, which is something that to Van Gaal's credit he has rarely done—Sergio Romero is probably the exception to that rule.
Bringing in players requires a substantial financial investment in terms of wages over time, and thus players brought in to do a job in the short term could end up causing a drag on the overall quality of the squad.
Whoever is brought in would simply have to be of the requisite standard to help address the two-and-a-half seasons of mediocrity that have followed Sir Alex Ferguson's retirement.
So a high-quality full-back or centre-back and a high-quality, flexible attacker are the two highest priorities in United's squad. Addressing those issues in January would be no mean feat, but it is only by doing so that United's hierarchy could consider the window a success.