The relationship between a landlord and tenant is one that tends to be disadvantageous to the tenant. This is because leases are drafted in favour of a landlord as much as possible (and we should know because we draft them) – built as a tenant, you have the right to negotiate the lease agreement.
You ideally want to ensure that the lease is reflects your interest and that you are not inadvertently entering into a long term contractual arrangement that comes back to bit you later on. We have many tenants come to us with issues mid-lease that could have been prevented has they received competent legal advice upfront.