The 2 biggest risks associated with Property Investment are Economic exposure & Tenant related risks.
Fixing rates reduces the first one and Insurance in particular Landlord Insurance minimises your tenant related issues.
Property investment is a business and LL insurance is just a cost of doing business.
IMHO it is a necessity if you are a serious investor.
I have been actively investing for the past 13 years and over that time have made 2 claims.
Its not a high cost expense either. For the sake of less than a weeks rent, that's also tax deductible, it provides fantastic peace of mind and is money well spent.