Death, taxes and Liverpool's front three consisting of Sadio Mané, Mohamed Salah and Roberto Firmino.
Not much in life is guaranteed, but since the summer of 2017, Jürgen Klopp's famed attacking trio have been untouchable. Until now, perhaps.
It's been well documented that Firmino's role in Klopp's well-oiled machine is far greater than to simply score goals, however, as a centre-forward, that is always going to be high on the priority list.
Often described as a 'defensive striker', the 29-year-old is expected to harass and press his opposition defenders into making mistakes, lay simple passes off to his attacking partners and drop deep in order to create space for Mane and Salah to sprint into. It's a simple yet extremely effective system that has brought the Reds unprecedented success in recent seasons.
While the side were winning multiple trophies and blowing teams away nobody really cared who was getting on the scoresheet, just as long as somebody was. But it's not gone unnoticed that Liverpool's Brazilian number nine has been struggling to find the back of the net on a consistent basis for the last couple of campaigns.
Throughout 2017/18, the Merseyside club were blowing teams away on their way to a fourth-placed finish and a Champions League final. Firmino hit a career-best 27 goals as well as providing 17 assists in all competitions.
Since then, the former Hoffenheim forward has suffered a steady decline. 16 goals followed in 2018/19 before that figure fell to just 12 last season. His assists have still been healthy with 21 over the last two seasons contributing to Liverpool's European and domestic success, although there surely comes a time when your starting striker has to take more of the goalscoring burden once again.
In the past, Firmino has arguably benefitted from a lack of options on Jurgen Klopp's bench. Divock Origi and Xherdan Shaqiri have popped up with some big performances and important goals without ever really pushing for a starting berth.
Injuries, inconsistency and question marks over whether they can seamlessly slot into Klopp's system have restricted the attacking duo's game time. Now there is a new pretender to Firmino's crown to contend with though.
After Diogo Jota's £40m move from Premier League rivals Wolves was confirmed, Liverpool's assistant manager Pep Lijnders told a press conference: "Diogo, what can I say? His technical level is on the same as our front three. He has so much future in his feet. He will have a great part (to play) inside our club. He is like a pressing monster. He will fit in straight away."
Lijnders' prediction came true. The Portuguese forward has bagged four goals in his first nine appearances for his new side. Firmino has one in ten this season.
Jota may have profited from coming on as a substitute and capitalising on tired legs in the opposition defence, although you can only beat what's put in front of you. The 23-year-old has scored important goals, including the winners against Sheffield United and West Ham over the weekend, which led to complimentary words from his manager.
After the late win over the Hammers, Klopp said: "We fought really hard to sign him. He's an exceptional talent. He has the speed, physicality, technique, he's both-footed. He's much better than I thought he would be and that's really impressive."
It's potentially premature to be calling for Liverpool's charismatic manager to wield the axe on one of his most important players. Liverpool are blessed with goalscorers across the pitch, allowing Firmino to become an expert in dropping deep, linking the play and creating the space for Mané and Salah, rather than having the goal-getting burden on his shoulders.
But, inevitably, there will be pressure on a number nine to score on a fairly regular basis - even in this Liverpool side.
Firmino's future may finally be under threat, then. He's proven his world-class quality on countless occasions, and it remains to be seen whether Jota can continue this form past the honeymoon period, but the summer acquisition is certainly giving Klopp a selection headache that he hasn't experienced over the past three seasons.
Source : 90min