As Muslims, from time to time, we discuss and ponder upon our condition in regards to what are genuine Islamic practices and what are newly conceived ideas.
Allah commands His slaves to refer all disputes to Him:
(And) if you differ in anything amongst yourselves, refer it to Allah and His Messenger.. 
It’s most often the case that the regular worshipers are utterly at dismay when they are told their practices are contravene to pristine Islam.
This is because of our ignorance in knowing the fundamentals of Islam and its governing principals. Further we are taught not to question the Imams or scholars which is diagonally opposite to Allah’s revelation.
When a human being is conceived as an absolute infallible, then corruption creeps into Allah’s deen.
Umar Ibn Al-Khattab (may Allah be pleased with him) said:
Islam will be destroyed by the mistakes of scholars, the arguments of the hypocrites who misinterpret the Qur’an to support their views and misleading rulers. 
Above statement by one of the greatest companion is timeless.
Shirk and Bi’dah v Qur’an and Sunnah
Our Nabi Muhammad (peace be upon him) didn’t leave any room for Shirk or Bi’dah (newly invented matter); knowing the former generations i.e. people of the book went astray from their own orthodox doctrines of their Prophets (peace be upon them all).
Towards the final years of the Messenger Muhammad (peace be upon him)’s life, he addressed the Muslims very frequently about deviant ideologies and cautioned the Ummah to strictly adhere to the Book of Allah, and his Sunnah.
I have left behind two things, you will never go astray as long as you hold fast onto them ie. the Qur’an and Sunnah. 
Of course every sect claims to follow these two pillars of Eemaan.
So how to distinguish between false claims and genuine claims?
In sha Allah, that is simple. The Qur’an and the Sunnah as they were understood and enacted by the noble companions (may Allah be pleased with them all) who graduated from the school of Muhammad (peace be upon him) and held certification from the last and final Messenger of Allah (peace be upon him), who said:
Pay attention to my sunnah (way) and the way of the Rightly-guided Khaleefahs after me, adhere to it and hold fast to it. 
In other words, if our practices contradict that of the companions of Rasulullah (peace be upon him), then rest assured our Islam is incorrect and will lead us to the flames of Jahannam. Prophet Muhammad (peace be upon him) said:
…The best of speech is the Book of Allah and the best of guidance is the guidance of Muhammad. The worst of things are those which are newly-invented, and every innovation is a going astray… 
This message ought to serve as a reminder to everyone who may seek guidance from none but Allah and His last and final Messenger (peace be upon him).
Abdullah bin Amr (may Allah be pleased with him) narrated the Prophet (peace be upon him) said:
“My Ummah will face what bani Israel faced step by step, even if one of them approached his mother publicly (sexually) there will be one of my Ummah will approach his mother.
And verily the Bani Israel divided into seventy two sects and my nation would divide into seventy three sects all are to hell except one (sect).“
We asked “which one is saved?”, the Prophet (peace be upon him) said: “Those who remain on which I and my companions remained.” 
Al-Shaafi’i (may Allah have mercy on him), said:
I do not know of anyone among the Sahaabah and Taabi’een who narrated a report from the Messenger of Allaah (peace be upon him) without accepting it, adhering to it and affirming that this was sunnah.
Those who came after the Taabi’een, and those whom we met did likewise: they all accepted the reports and took them to be sunnah, praising those who followed them and criticizing those who went against them.
Whoever deviated from this path would be regarded by us as having deviated from the way of the Companions of the Prophet (peace be upon him) and the scholars who followed them, and would be considered as one of the ignorant.
Authored by Jamal Mohamed Ashraf
 Qur’an | al-Nisaa’ 4:59
 Mahd as-Sawab, 2/717
 Saheeh Abi Dawud, Kitaab al-Sunnah
 Muwatta Imaam Maalik, 1601
 Muslim, 867
 Tirmidhi: 2651