MC
DLA renewals are treated as new claims, also the DWP are looking at your condition now, so if you can provide new evidence then it is to your advantage to do so.
If you cannot, then you can still use your previous evidence, but you will need to show that this evidence is still relevant to your condition now. This may not be a problem if your conditions are not likely to improve, but if this is not the case, it may be more difficult to prove your claim.
If you haven't already, please refer to the DLA claim guides, see
www.benefitsandwork.co.uk/help-for-claimants/dla/#dlaclaims Gordon