What are the purposes of each of your example adjusting entries?

Describe at least two typical adjusting entries a service-type business would need to record to bring account balances up-to-date.

What are the purposes of each of your example adjusting entries?
Why are these adjusting entries required?
What if the company does not record these adjusting entries? Would financial statements be accurate? Why or why not?
Should the adjusting entries described be posted to the general ledger before preparing an adjusted trial balance? Why or why not?
Beyond the explanations above, post the actual adjusting entries (with accounts, debits and credits) for each of your examples.