Some days it pays to take it easy. “If you have other stressors going on in your life, you don’t need to be killing yourself through exercise,” says San Diego-based strength and conditioning coach Pete McCall. However, if you’re chasing a goal — whether weight loss, greater strength or your first marathon — you need to keep challenging yourself in order to make progress.

Slacking off too long at the gym doesn't give your body the necessary stimulus it needs to adapt to be able to lift more weight, run farther and faster or burn fat more efficiently, says Albert Matheny, RD, co-founder of SoHo Strength Lab and adviser to Promix Nutrition. So here are the top five signs that you could be doing more during your workouts.

You should expect strength gains after about four to six weeks of consistent training, says strength and conditioning coach Erica Suter. So if you’re working toward your one-rep maximum squat (or the most weight you can safely squat for a single rep), but your numbers haven’t budged after six weeks, you may need to tweak your intensity.

For strength goals, this means keeping your reps on the lower side (one to five) and gradually increasing the weight every couple of weeks, Suter says. If you’re still relatively new to lifting weights (i.e., less than one year), stick with three sets of eight to 12 reps for every exercise, says strength coach Albert Matheny. Add more weight once you can complete 12 reps with good form.

Some soreness within the first 24 to 48 hours after a workout can be a good thing. Also known as delayed onset muscle soreness (DOMS), a little bit of achiness indicates you worked hard enough to damage your muscle fibers, which will lead them to recover and grow back stronger when fueled by proper nutrition. While you won’t want to feel sore every day, if you’re never sore post-workout, it could be time to put in more work.

Strength coach Erica Suter recommends gradually increasing your training volume or switching up the types of movements you’re doing. This could mean going from two workouts per week to three, incorporating drop sets or eccentrics if you’re lifting weights or adding an extra set or two of sprints if speed is your goal.

Read more: Get Serious Results With One Simple Strength Training Change

Not every run should be killer, but if you’re looking to become a speed demon, you need at least a couple of high-intensity sessions per week. The best way to measure your effort on high-intensity days is if you’re able to form full sentences during the hardest parts of the workout. If you’re chatting the minutes away, it’s time to bump up the speed, says personal trainer Pete McCall.

For those who like to catch up on their favorite shows while they’re running on the treadmill, McCall recommends increasing the effort during commercials. This will translate into two to three minutes at a hard-pace effort followed by seven to nine minutes at an easy recovery pace. Aim for two, but no more than four, high-intensity workouts per week, giving yourself at least one full day of rest in between sessions.

Tuning into your rate of perceived exertion (RPE), or how hard you feel like your body is working, will tell you if you’ve been slacking. You can use the Borg Scale to rate your RPE, where nine corresponds to “very light” exercise, 13 is “somewhat hard,” and 17 is “very hard.” But personal trainer Pete McCall prefers to use a scale of one to 10. One means you’re sitting on the couch, while 10 refers to an all-out sprint.

“It’s all based on your perception,” McCall says. “What’s hard for you?” On easy days, you should fall between a five and a seven. At this rate, you should be able to carry a conversation. On hard days, aim for a seven or eight. At this level, you should only be able to manage a word here or there, but nothing more. Start tracking RPE along with the rest of your training notes so you can gauge how you’re responding to workout intensity over time.

It’s normal to have an off day. Or two. But if your workouts always have you bored to tears, it could be a sign that you’ve been doing the same thing for too long and you need a new challenge. Take this opportunity to re-evaluate your goals. “People need to ask themselves, ‘What do I want next?’” strength coach Erica Suter says.

Are you chasing strength? Trying to lose weight? Do you simply want to feel a burn after your workout? Checking in with your goals will help you decide on the best way to challenge yourself. Once you’re feeling reinvigorated by your routine, you can start manipulating the variables of your workout — intensity, frequency, load — to continue making progress.

Read more: 11 Simple Ways to Add Variety to Your Strength-Training Routine

What’s your current workout routine like? After reading this, do you think your workout is a bit too easy? Or maybe it’s too hard. Neither is a good option. What will you change about your workout? Are there any other warning signs you’ve seen that your workout isn’t hard enough to challenge you? Share your thoughts with us in the comments below!