alot of this debate came out of the crash of an ifr aztec back in the late 80s  where the pilot cancelled ifr  crashed on approach  nobody knew what happened until the next  aircraft on an ifr approach  into the same airport reported it.    cancelling  ifr  and holding alerting services  is your protection against that ) and cancelling ifr and holding alerting  is alslo the courtesy way  expediting   ifr traffic flow into /out of uncontrolled  busy airports on vfr days   of Here are a couple of  typical  conversations  for those flying 703/704 in the north 
scenario #1
ywg center  c-grub   
c-grub ywg
c-grub  requesting descent 
ywg atc  > cleared out of  controlled airspace in the vicinity  of upper rubber boot  Manitoba  call thur  12500  we  show no traffic between you and destination 
c-grub   cleared out controlled airspace in the vicinity of  upper rubber boot Manitoba  will call thru 12500  
 decent checks done decent ,begins  decent  ,approach  briefing  ( some sop's do it by distance. some by time to landing for app briefing. others before initiating decent )  and radio calls on 126.7   an  after  12,500  call to ywg atc .   thru say 11,000     presto   vfr at the 2am 
 you 
dont need to advise  atc that you are cancelling ifr  because  you  on an ifr itinerary   atc will come looking for you  at the expired time on the itinerary  .It is very useful for when medics  get delayed  at clinics  I used  2hour window for  sar  and update  eta before you lose  radio coverage  with center.
the nice part of  ifr itineraries  is the re entry in to controlled airspace   on the way south      
>atc this c-grub  
c-grub  ywg go ahead 
atc c-grub climbing thru 9000 looking to pick up the  ifr to ywg    
might need to get   bit  higher depending on sector to get pal coverage   but  atc knows your   leaving  upper rubber boot   and expected to be in their sector of responsibility .  getting transponder code   is  faster too  ( most Times) 
scenario #2  
atc 
c-grub is cleared out controlled airspace in the  vicinity of   Norway house   minimum  100 mile safe ifr altitude  out  of Thompson  is (I don't have the chart in front of me so chill )4000ft   its a Cavok  so you cancel ifr but hold the alerting    and will call down on the triple 1888 number 
the important thing to know is you cannot use an ifr itinerary if you are going to enter controlled airspace more  than one exit and one re- entry (  yes i know the door is open on that one but  ladies fly too and so  lets   step up our decorum gents ) 
Note some fss /  controllers will not let you file IFR  itinerary  if on your descent out hi level controlled  you pass thru a low level controlled sector  even if briefly en route to the uncontrolled  airport    area around red lake  to pikangikum  / popular hill as an example comes to mind   depending on direction inbound
finally its the peace of mind factor if you feel your company dispatch is unreliable   which can happen in small operations when the owner/mgr been awake  for days running on min rest and it 2am  // the  ifr  itinerary  allows  you to go do the job  into remote places  or  rural towns.   knowing  that when time is up on the iten atc will start making phone calls on your behalf to find  you     fly safe  
