An Nawawi said: "it is preferred to say (in the name of Allah) and repeat (remembrance) of Allah frequently".
1. Mentioning regards to Allah
The Prophet (peace be upon him) said: "when a man mention Allah while entering his house and when he eats, the devil says to his mates (there is no food or shelter for this night for you) " [Muslim, The Book of Drinks, Hadith 2018]
2. Entrance Du'aa
The Prophet (peace be upon him) said: " say
"بِسْمِ اللهِ وَلَجْنَا، وَ بِسْمِ اللهِ خَرَجْنَا، وَعَلَى رَبِّنَا تَوَكَّلْنَا".
Bismillaahi walajnaa, wa bismillaahi kharajnaa, wa 'alaaRabblnaa tawakkalnaa (O Allah I ask you the best out of entrance and the best out of exit, I enter in the name of Allah and exit in the name of Allah, I put my trust in Allah) then salute his family. (say As-Salaamu 'Alaykum)"
[Aboo Dawood, The Book of Good Manners, Hadith 5096]
This is the way a man depends on Allah while entering or exiting, which keeps him/her always connected to Allah.
3. Using Sewak
Imam Muslim narrated that the Prophet (peace be upon him) used Sewak while taking his first steps into home. [Muslim, The Book of Purification, Hadith 253]
Allah says: "So when you enter houses, salute one another (Literally: salute yourselves) with a greeting from the Providence of Allah, blessed and good". (An Noor :61)
Supposing that a Muslim who goes for prayers in the Mosque practice these Sunnahs; that would make 20 Sunnahs aday.
5. Going out
A Muslim should say this du'aa :
"بِسْمِ اللهِ، تَوَكَّلْتُ عَلَى اللهِ، وَلَا حَوْلَ وَلَا قُوَّةَ إِلَّا بِاللهِ".
Bismillaahi, tawakkaltu 'alallaahi, wa laa hawla wa laa quwwata ‘ illaa billaah. (in the name of Allah, I put my trust in Allah, Whatever Allah wishes will be; there is no strength except from Allah) so he gets protected, secured, guarded and the devil steps away from him)
[Aboo Dawood, The Book of Good Manners, Hadith 5095; At-Tirmidhee, The Book of Supplication, Hadith 3426]
The outcome of the application of these sunnahs:
1- A Muslim gets protected from whatever evil he gets in touch with.
2- A Muslim gets secured from whatever evil that might hurt him.
3- A Muslim gets guided and guarded in everything either divine or secular.