When I first needed support at the time I had a choice of opting for the DLA or apply for the new PIP
As DLA was at the early stages of being phased out I opted to go for PIP
I could have gone for DLA a year or so earlier but I waited until I had undergone and exhausted all of the conservative treatment options made available/offered to me.
Also being on ESA I was aware that I should be in the support group and not WRAG so I waited before applying for PIP until this was possible
Prognosis was made ( some 5yrs after seeking initial treatment) and on the strength of this I asked for a ESA super-session which thankfully then placed me in the HIGHER support group
I gathered as much supporting medical evidence from as many people as I could
On the strength of this I then applied and won my PIP award
Always remember fluctuating conditions will attract a shorter award as thing can get better as well as worse
If an assessor tells lies then complain directly to the company that employs the assessor do not get distracted by this and quickly move on with countering those lies with strong supporting evidence as just proving a assessor to be a liar will not win you an award
Never accept an offer for an over the phone application always go online and seek a DWP SAR request ( Subject access request) they will if asked send you all past info that they have about you ( can be an eye opener ) at the very least it will give you a detailed insight that can be very useful
Good thing is this request is free and they have 40 days to send this out to you so always best to ask for this asap as may well prove useful in future reviews
I could write so much about all of this but I have touched on the main points