Your call- it is really just to catch the drips while you are drinking your drink. A small piece of tupperware can do the same.
These little guys have a problem developing some moisture issues under neath already. Heating and cooling of the base / via the boiler. Trapped condensation, tiny leaks- drips from the driptray area via the screw that holds on the base cover etc. A drip catch of some kind will help mitigate this a little.
These little guys will do you a great job. New group seals maybe as often as once a year to as little as every 3 or so. They also like some lube. So if you do not have any foodsafe / heat tolerant lube you check into a tube also- It will last a life time- but something that is important to have.
As far as the whole seal kit- You might just wait on the whole or compare the price of the whole vs the group seals only and see what makes sense- neither is a boat load of money and is a skill easy to acquire and really helps you feel confident with your machine.
Does you boiler look clean inside? If you do have any scale build up- some generic citric acid from a home brewing store( cheap -cheap) will wipe out any traces- if you see no big evidence- then don't over think it. Use Brita water pitcher water. Brita softens and filters your water. Dump your boiler completely maybe every week so you don;t have stale water building up. That can be a personal deal- every day is great- every two weeks or so may not even be noticeable to you.
Have fun- the only real mistake you can do is not getting used to topping the water ever time you prep for coffee - before you power up. Then DO NOT get side tracked on the phone, then forget what you are doing- I.E leave for work and go " DoH"
The later is why you ALWAYS have a full boiler- you can always come back an hour later with a full boiler and just turn off the machine. One left on with a very low boiler could cost you money on an element! A two switch element is expensive- about $145 without shipping!
Develop a routine and it will save you heart ache!