Hi leed,
Contributary benefits are awarded when the claimant has the required number of NI contributions made in recent tax years. These can only be gained through working (people on IB have been transferred to contributary ESA even though they have not worked recently).
Claimants who have not made the neccessary NI contributions are 'means tested' to see if they are eligible for income-related benefits. This depends upon the household income and savings, also on whether the live-in partner, if there is one, works more than 24 hours per week.
People on income-related ESA are automatically entitled to other things, such as free prescriptions.
ESA in the WRAG is time-limited to 365 days after which the means-test comes into effect. There is no such limit to ESA in the Support Group.
It is possible to get an income-related top-up to contributary ESA if the claimant has a very low income. It is worth asking DWP for an ESA3 form if it is thought that this might be the case.
24 hour work rule for ESA(IR) Asset rule for ESA(IR) I hope this helps!