There's some who wait until they're in a hospital bed before going on immunomodulators/biologics, there's some who use them for mild symptoms, or anywhere in between. It always comes down to personal preference (bottom-up-approach, or a top-down-approach).
A lot of gastereoenteroligists are proponents for the top-down approach, using biologics/immunomodulators much sooner to quell UC sooner, control it fast while it is limited in extent and severity, before it's a huge problem. Would you rather put out a fire when there's a small ember glowing or wait until the entire house is on fire? A swift, strong response early on can result in the least trouble, the best quality of life, and the least struggling and suffering.
There's merit and firm believers in the bottom-up-approach, always starting with mesalamines, and escalating slowly over time to use the least amount of meds first. There's benefits to staying on only mesalamines for those for whom that is sufficient for longterm remissions, lower risk etc.
In the end there's risk to everything, risk of uncontrolled, longterm UC inflammation causing a colorectal cancer, potential risk from a UC med, risk in doing nothing or something. I believe it is important to at least quantify what are the odds of side effects from immunomodulators and biologics. To put that risk into perspective, whether or not you need those medications today or not. Here's a good read/watch on it, that discusses the side effects and odds of them occurring from the Crohn's and Colitis Foundation of America:
Webcast:
programs.rmei.com/CCFA139VL/presentation/player.htmlTranscript
: http://www.ccfa.org/assets/pdfs/risk-and-benefits-transcript
.pdf
I've been on 6MP and Remicade since 2012, have experienced a remission, and have had zero side effects. Side effects are rare but serious when they do occur.
It always comes down to can you control your UC now with what you are doing. Give it more time and see. However, there's CRC risks associated with doing nothing longterm with inflammation being untreated.