Practical implications of relaxation

In general terms, T2 influences linewidths of an NMR spectrum whereas influences relative intensities. 

It is clearly advantageous to maximise T2, which can be achieved by using lower concentrations, less viscous solvents and higher temperatures. However, in practice, there are frequently other contributions to the linewidth, such as inhomogeneities in Bq or unresolved chemical shifts and coupling constants which are not affected by changes in sample conditions. These other factors are often dominant in polymer NMR, and usually the FID has decayed well before the longitudinal component has recovered. 

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