Necessities for going bigger than 33?

Im still a newbie but Ive had this question for a while. For over a year now I have been constantly seeing people give other people a hard time for getting 35 or 37 inch tires without reinforcing their axle with gussets and such and for not re-gearing as well. Id like to know if its really that necessary to do these things, especially since my jeep (as well as 3 other friends) have JK/JKUs that we bought and simply threw on a 2.5 inch lift and 35 inch tires (Nitto Trail Grappler). We mainly do a lot of really bad mud and some light trails and have never had any problems with something breaking or going wrong or complained about the stock gearing. We want to take a trip to Marble Falls in Texas soon and have a good time, but constantly seeing comments like "have fun breaking your axle" on people's posts online have really had me scared for over a year lol. Could we get some more information about this kind of stuff? A lot of the things people do to their axles and stuff seem like overkill and pretty dang expensive for a bunch of 18-20 year olds haha. Thanks guys!